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You searched for subject:( CFD ). Showing records 1 – 30 of 3227 total matches.
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1. Camp, Joshua Lane. Massively-parallel Spectral Element Algorithm Development for High Speed Flows.
Degree: 2013, Texas Digital Library
URL: http://hdl.handle.net/1969;  http://hdl.handle.net/2249.1/66581
► The need to reduce both the time and cost of product design has allowed numerical analysis to play an ever-increasing role in design cycle analysis.… (more)
▼ The need to reduce both the time and cost of product design has allowed numerical analysis to play an ever-increasing role in design cycle analysis. This is particularly true in the aerospace industry, where the use of computational fluid dynamics can help reduce the need for costly prototype testing. Due to the extremely high computational costs associated with simulating complex industrial flows directly, most modern simulation tools employ solvers that rely heavily on turbulence modeling. However, the combination of modern supercomputers and algorithms that can take full advantage of them allows for higher fidelity solvers, with reduced dependence on turbulence modeling, to be included in design cycle analysis. This work employs the discontinuous Galerkin spectral element method in a solver designed for high fidelity simulations in the subsonic and transonic flow regimes. The algorithm is implemented using NEK5000, an open-source incompressible spectral element solver, as a code base. Details of the algorithm are given, and the code is validated against several canonical inviscid and viscous test cases. The validation cases show that the code is accurate, stable, and a good performer on supercom- puters. The new solver is then used to study the effectiveness of a cylindrical film cooling hole. The results show a much improved prediction capability of film cooling effectivness as compared to previous low-Mach simulation results. The algorithm is proven to produce quality large-eddy simulation data in a time frame accessible for design cycle analysis. At the end, a suggested direction for future development of the algorithm is discussed, with a focus on how to improve the stability and performance of the solver. Advisors/Committee Members: Duggleby, Andrew (advisor).
Subjects/Keywords: CFD
Camp, J. L. (2013). Massively-parallel Spectral Element Algorithm Development for High Speed Flows . (Thesis). Texas Digital Library. Retrieved from http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66581
Camp, Joshua Lane. "Massively-parallel Spectral Element Algorithm Development for High Speed Flows." 2013. Thesis, Texas Digital Library. Accessed January 19, 2021. http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66581.
Camp, Joshua Lane. "Massively-parallel Spectral Element Algorithm Development for High Speed Flows." 2013. Web. 19 Jan 2021.
Camp JL. Massively-parallel Spectral Element Algorithm Development for High Speed Flows. [Internet] [Thesis]. Texas Digital Library; 2013. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66581.
Camp JL. Massively-parallel Spectral Element Algorithm Development for High Speed Flows. [Thesis]. Texas Digital Library; 2013. Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66581
2. Roth, Gable D. CFD analysis of pressure differentials in a plate-type fuel assembly.
Degree: MS, Nuclear Engineering, 2011, Oregon State University
► The Hydro-Mechanical Fuel Test Facility (HMFTF) is being built at Oregon State University to evaluate fluid flow through plate-type fuel assemblies. The first plate assembly… (more)
▼ The Hydro-Mechanical Fuel Test Facility (HMFTF) is being built at Oregon State University to evaluate fluid flow through plate-type fuel assemblies. The first plate assembly that will be examined in the facility is the Generic Test Plate Assembly (GTPA). The GTPA consists of an array of six parallel flat plates, 24 inches long, forming seven flow channels. The plates are a total of 4 inches wide and 0.05 inches thick with 0.25 inches of the plate edge being imbedded in the side plate making a flow channel of 3.5 inches wide. The height of the flow channels is adjustable. A support comb is used to stiffen the free edges of the fuel plates. The Star-CCM+ CFD tool was used to analyze fluid flow through the GTPA with channels of equal height (0.075 inches) except for the middle channel which was 0.125 inches high. Using standard CFD practices the mesh type, mesh size, and turbulence model were selected. Using different boundary conditions, consisting of three flow rates with a fixed temperature and three temperatures, with the flow rate fixed at one of the three analyzed flow rates, the pressure differentials between the channels were analyzed to determine the possibility of plate deflection. The analysis revealed that the pressure difference between the channels increased with increasing volumetric flow rate. The results also indicate that as the system temperature increased the pressure differential between the channels decreased slightly. Velocity results were compared to Miller's critical velocity and indicate that plate deflection is not expected to occur at the inlet of the channel due to the stiffening caused by the presence of the support comb. Advisors/Committee Members: Woods, Brian G. (advisor), Carozza, Susan E. (committee member).
Roth, G. D. (2011). CFD analysis of pressure differentials in a plate-type fuel assembly . (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/21807
Roth, Gable D. "CFD analysis of pressure differentials in a plate-type fuel assembly." 2011. Masters Thesis, Oregon State University. Accessed January 19, 2021. http://hdl.handle.net/1957/21807.
Roth, Gable D. "CFD analysis of pressure differentials in a plate-type fuel assembly." 2011. Web. 19 Jan 2021.
Roth GD. CFD analysis of pressure differentials in a plate-type fuel assembly. [Internet] [Masters thesis]. Oregon State University; 2011. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1957/21807.
Roth GD. CFD analysis of pressure differentials in a plate-type fuel assembly. [Masters Thesis]. Oregon State University; 2011. Available from: http://hdl.handle.net/1957/21807
3. Zhou, Yuping. Investigation of applying CFD models to 3D wind turbine simulation.
Degree: Mechanical & Manufacturing Engineering, 2017, University of New South Wales
URL: http://handle.unsw.edu.au/1959.4/58670  ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46588/SOURCE02?view=true
► CFD simulation is becoming a more and more popular tool for analyzing wind turbine performance. This thesis studies the effect of various CFD models on… (more)
▼ CFD simulation is becoming a more and more popular tool for analyzing wind turbine performance. This thesis studies the effect of various CFD models on 3D wind turbine simulation by conducting simulations on the NREL PHASE VI wind turbine which is linearly taped and non-linearly twisted. The configuration of NREL PHASE VI in this thesis is 10 meters long in diameter, 𝟎 ° yaw angle, 𝟑 ° pitch angle at the tip and rotating at a constant angular velocity of 72 RPM. An accurate 3D model of NREL Phase VI turbine is created to which various CFD models with different mesh configurations, including structured and unstructured mesh, and turbulence models are applied to study their ability to capture flow behaviors, such as flow separation, and measure flow quantity such as wind turbine torque. Unstructured mesh with SST turbulence model was found to output results which have the best agreement with the experiment results in terms of generated shaft torque and the intensity of flow separation at various wind speed. Intense flow separation at a wind speed of 10m/s was observed in both structured and unstructured mesh model. It was also found that over-prediction of flow separation will lead to the under-prediction of shaft torque for every turbulence model tested in this thesis. Advisors/Committee Members: Yeoh , Guan Heng, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW, Page, John Randall, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW.
Zhou, Y. (2017). Investigation of applying CFD models to 3D wind turbine simulation . (Masters Thesis). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/58670 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46588/SOURCE02?view=true
Zhou, Yuping. "Investigation of applying CFD models to 3D wind turbine simulation." 2017. Masters Thesis, University of New South Wales. Accessed January 19, 2021. http://handle.unsw.edu.au/1959.4/58670 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46588/SOURCE02?view=true.
Zhou, Yuping. "Investigation of applying CFD models to 3D wind turbine simulation." 2017. Web. 19 Jan 2021.
Zhou Y. Investigation of applying CFD models to 3D wind turbine simulation. [Internet] [Masters thesis]. University of New South Wales; 2017. [cited 2021 Jan 19]. Available from: http://handle.unsw.edu.au/1959.4/58670 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46588/SOURCE02?view=true.
Zhou Y. Investigation of applying CFD models to 3D wind turbine simulation. [Masters Thesis]. University of New South Wales; 2017. Available from: http://handle.unsw.edu.au/1959.4/58670 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46588/SOURCE02?view=true
4. Douglas, Joseph Philips. A detailed look into the aerodynamic forces due to the drag-reducing aerospike.
Degree: MS, Aerospace Engineering, 2016, Mississippi State University
URL: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10282016-144645/  ;
► This thesis aims to simulate previous wind tunnel experiments on the drag-reducing aerospike in order to help validate the accuracy of CFD analysis. Multiple… (more)
▼ This thesis aims to simulate previous wind tunnel experiments on the drag-reducing aerospike in order to help validate the accuracy of CFD analysis. Multiple grids were created with the Pointwise grid generation software. The CFD analysis software used was Ansys Fluent, with both planar and axisymmetric cases being tested for the primary rocket in order to compare the differences. The tests with the primary rocket followed how a spike of set length reacted at various speeds. Two additional experiments were duplicated. These helped confirm that the results obtained via Fluent were accurate. One case was a simple transonic spike model, and the other was a more complex hypersonic model. The results from both cases matched well with wind tunnel tests, validating results for the primary rocket. This thesis paves the way for anyone wanting to continue a more in depth study into the flow properties of any type of projectile. Advisors/Committee Members: Keith Koenig (chair), Greg Olsen (committee member), Keith Walters (committee member).
Subjects/Keywords: aerospike; CFD
Douglas, J. P. (2016). A detailed look into the aerodynamic forces due to the drag-reducing aerospike . (Masters Thesis). Mississippi State University. Retrieved from http://sun.library.msstate.edu/ETD-db/theses/available/etd-10282016-144645/ ;
Douglas, Joseph Philips. "A detailed look into the aerodynamic forces due to the drag-reducing aerospike." 2016. Masters Thesis, Mississippi State University. Accessed January 19, 2021. http://sun.library.msstate.edu/ETD-db/theses/available/etd-10282016-144645/ ;.
Douglas, Joseph Philips. "A detailed look into the aerodynamic forces due to the drag-reducing aerospike." 2016. Web. 19 Jan 2021.
Douglas JP. A detailed look into the aerodynamic forces due to the drag-reducing aerospike. [Internet] [Masters thesis]. Mississippi State University; 2016. [cited 2021 Jan 19]. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10282016-144645/ ;.
Douglas JP. A detailed look into the aerodynamic forces due to the drag-reducing aerospike. [Masters Thesis]. Mississippi State University; 2016. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10282016-144645/ ;
5. Anumolu, Pratima. Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury.
Degree: MS, Biomedical Engineering, 2014, Texas A&M University
URL: http://hdl.handle.net/1969.1/153530
► Over the last decade, soldiers fighting in Iraq and Afghanistan are being exposed to blasts from powerful explosives with improvised detonation techniques. These blasts put… (more)
▼ Over the last decade, soldiers fighting in Iraq and Afghanistan are being exposed to blasts from powerful explosives with improvised detonation techniques. These blasts put them at high risk of closed head non-impact Blast-induced Traumatic Blast Injury (bTBI). bTBI is caused by interaction of shock-wave. It is a debilitating condition, but goes undiagnosed for several months. The pathology of bTBI is poorly understood making diagnosis, treatment, and prevention of bTBI difficult. One way to study it is to construct a shock tube that replicate blast profile. However, this method does not replicate blast conditions perfectly. The goal of this research is to improve shock tube as a research tool, for studying bTBI, by better replicating military ordnance. Various 2D models to simulate the shock wave propagation in a shock tube to see the effects of varying shock tube geometry and working fluid on the blast profiles were developed. Ranges of different parameters evaluated are: tube length - 5ft to 25ft; tube diameter - 8" to 16"; working fluid - compressed air and helium; burst pressure- 20 to 55 psi. A total of 240 simulations were run to evaluate the effect of these factors on the pressure profile. Computations were carried out using commercial software, Star CCM+ (CD-adapco, NY, USA). Assumptions used to model the flow were unsteady, inviscid, compressible, axisymmetric flow with time-step of 1e-5s. Multiple regression was run on these parameters to establish empirical relationship with pressure profile. CFD model was validated using experimental data from Robbins-Moreno shock tube. Results show that as the burst pressure increases, peak overpressure, positive phase duration, and impulse also increase. Increasing tube diameter decreases peak. Change in tube length does not have a significant effect on peak overpressure, positive phase duration, and impulse. Working fluid was most significant factor determining the magnitude of impulse and duration. In conclusion, the empirical formulas developed using CFD model of the shock tube provide reasonable predictions about the key features of a pressure profile that and their dependence on the shock tube geometry, working fluid, and burst pressure. This knowledge will be used to improve shock tube to study bTBI. Advisors/Committee Members: Moreno, Michael (advisor), Criscione, John (committee member), van Loon, Raoul (committee member), Ranjan, Devesh (committee member).
Subjects/Keywords: bTBI; CFD
Anumolu, P. (2014). Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury . (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/153530
Anumolu, Pratima. "Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury." 2014. Masters Thesis, Texas A&M University. Accessed January 19, 2021. http://hdl.handle.net/1969.1/153530.
Anumolu, Pratima. "Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury." 2014. Web. 19 Jan 2021.
Anumolu P. Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury. [Internet] [Masters thesis]. Texas A&M University; 2014. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1969.1/153530.
Anumolu P. Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury. [Masters Thesis]. Texas A&M University; 2014. Available from: http://hdl.handle.net/1969.1/153530
6. Peña, Christopher. Computational Fluid Dynamic Analysis of AxWJ-2 Propulsor Cavitation Breakdown .
Degree: 2011, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/11559
► For waterjet systems operating in marine ships, cavitation is a phenomenon that often occurs. The presence of vapor in the flow affects the performance of… (more)
▼ For waterjet systems operating in marine ships, cavitation is a phenomenon that often occurs. The presence of vapor in the flow affects the performance of the pump and as the cavity grows the pump efficiency drastically reduces to a level where the pump cannot operate normally. Due to this influence on the pump performance it is of main interest to be able to predict the behavior of the cavitation process. At Johns Hopkins University and the Naval Surface Warfare Center Carderock Division (NSWCCD), researchers have designed, fabricated, and tested an axial flow waterjet pump (AXWJ-2). Measurements of the total head rise and shaft torque on flow through the pump have been taken at a range of flow conditions through cavitation breakdown. The aim of this thesis is to compare and analyze the results of the AXWJ-2 experiment with a numerical cavitation model. The numerical model applies a Reynolds-Averaged Navier Stokes method. The flow solver uses a locally homogeneous multiphase approach coupled with a liquid-vapor mass transfer model. Numerical solutions appear to accurately capture the integrated performance at all conditions. Results start to deviate at low tunnel pressures due to choking cavitation since the experiment includes decreasing flow rates while the CFD keeps a steady flow rate. Choking is seen to occur due to saturation of low pressure at the exit of the rotor passageway. Advisors/Committee Members: Jules Washington Lindau V, Thesis Advisor/Co-Advisor, Jules Washington Lindau V, Thesis Advisor/Co-Advisor, Robert Francis Kunz, Thesis Advisor/Co-Advisor.
Subjects/Keywords: Cavitation; CFD
Peña, C. (2011). Computational Fluid Dynamic Analysis of AxWJ-2 Propulsor Cavitation Breakdown . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/11559
Peña, Christopher. "Computational Fluid Dynamic Analysis of AxWJ-2 Propulsor Cavitation Breakdown ." 2011. Thesis, Penn State University. Accessed January 19, 2021. https://submit-etda.libraries.psu.edu/catalog/11559.
Peña, Christopher. "Computational Fluid Dynamic Analysis of AxWJ-2 Propulsor Cavitation Breakdown ." 2011. Web. 19 Jan 2021.
Peña C. Computational Fluid Dynamic Analysis of AxWJ-2 Propulsor Cavitation Breakdown . [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Jan 19]. Available from: https://submit-etda.libraries.psu.edu/catalog/11559.
Peña C. Computational Fluid Dynamic Analysis of AxWJ-2 Propulsor Cavitation Breakdown . [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/11559
7. Medvitz, Richard B. DEVELOPMENT AND VALIDATION OF A COMPUTATIONAL FLUID DYNAMIC METHODOLOGY FOR BLOOD PUMP DESIGN ANALYSIS AND PREDICTION OF THROMBUS POTENTIAL.
URL: https://submit-etda.libraries.psu.edu/catalog/8126
This is or my format review. Advisors/Committee Members: Eric G Paterson, Committee Chair/Co-Chair, John Michael Cimbala, Committee Member, Arnold Anthony Fontaine, Committee Member, Daniel Connell Haworth, Committee Member, Robert Francis Kunz, Committee Member, Leomard Joel Peltier, Committee Member.
Medvitz, R. B. (2008). DEVELOPMENT AND VALIDATION OF A COMPUTATIONAL FLUID DYNAMIC METHODOLOGY FOR BLOOD PUMP DESIGN ANALYSIS AND PREDICTION OF THROMBUS POTENTIAL . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/8126
Medvitz, Richard B. "DEVELOPMENT AND VALIDATION OF A COMPUTATIONAL FLUID DYNAMIC METHODOLOGY FOR BLOOD PUMP DESIGN ANALYSIS AND PREDICTION OF THROMBUS POTENTIAL." 2008. Thesis, Penn State University. Accessed January 19, 2021. https://submit-etda.libraries.psu.edu/catalog/8126.
Medvitz, Richard B. "DEVELOPMENT AND VALIDATION OF A COMPUTATIONAL FLUID DYNAMIC METHODOLOGY FOR BLOOD PUMP DESIGN ANALYSIS AND PREDICTION OF THROMBUS POTENTIAL." 2008. Web. 19 Jan 2021.
Medvitz RB. DEVELOPMENT AND VALIDATION OF A COMPUTATIONAL FLUID DYNAMIC METHODOLOGY FOR BLOOD PUMP DESIGN ANALYSIS AND PREDICTION OF THROMBUS POTENTIAL. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 19]. Available from: https://submit-etda.libraries.psu.edu/catalog/8126.
Medvitz RB. DEVELOPMENT AND VALIDATION OF A COMPUTATIONAL FLUID DYNAMIC METHODOLOGY FOR BLOOD PUMP DESIGN ANALYSIS AND PREDICTION OF THROMBUS POTENTIAL. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/8126
8. Songyu, Cao. Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion .
Degree: 2015, University of Ottawa
► Cable-stayed bridges are massive structures which rely on their structural elements such as deck girder, towers and stay-cables for their stability. The bridge stay-cables can… (more)
▼ Cable-stayed bridges are massive structures which rely on their structural elements such as deck girder, towers and stay-cables for their stability. The bridge stay-cables can be considered as the most flexible elements of the cable-stayed bridges, and thus their structural stability integrity is verified for several phenomena which might affect them. Wind and wind/rain induced vibrations for bridge stay-cables were comprehensively studied by researchers worldwide; however recent projects have identified a new type of cable vibrations caused by ice accretion formed around the cable circumference. The current research proposed two ice accretion profiles for inclined bridge cables and has experimentally investigated the wind-induced vibrations of the two models for the bridge stay-cables with ice accretion, under different vertical (inclination) and horizontal (yaw) angles, and for different wind speeds. Initially, three models of the bridge cable with 1.0 cm and 2.0 cm ice profile were tested in the wind tunnel of cross-section 61 cm × 90 cm, and a maximum wind speed of 30 m/s. In total 6 cases with 1.0 cm ice thickness and 3 cases with 2.0 cm ice thickness were investigated and the vertical and torsional oscillatory displacements were recorded for wind speeds from 1.5 m/s to 15 m/s at intervals of 1.5 m/s. The wind-induced vibrations were analyzed and were compared with the response reported for cables without ice and with the rain-induced response for stay-cables. Computational Fluid Dynamics (CFD) simulations were performed to observe the drag, lift and pressure coefficients around the surface of the accreted cable models yawed and inclined at α = 0°, β = 0° and α = 60°, β = 15° under the effect of 10 m/s and 15 m/s wind speed applied for both cases. A verification for galloping divergent instability was conducted based on the Den Hartog formulation and the vertical vibrations obtained from the wind tunnel experiment.
Subjects/Keywords: Galloping; CFD
Songyu, C. (2015). Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion . (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/32985
Songyu, Cao. "Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion ." 2015. Thesis, University of Ottawa. Accessed January 19, 2021. http://hdl.handle.net/10393/32985.
Songyu, Cao. "Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion ." 2015. Web. 19 Jan 2021.
Songyu C. Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion . [Internet] [Thesis]. University of Ottawa; 2015. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/10393/32985.
Songyu C. Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion . [Thesis]. University of Ottawa; 2015. Available from: http://hdl.handle.net/10393/32985
9. Ma, Man Ching. Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame using Conditional Moment Closure Method.
Degree: 2014, University of Waterloo
► The effects of differential diffusion in the numerical modelling of a turbulent non-premixed hydrogen-air jet flame using a Conditional Moment Closure (CMC) method are investigated.… (more)
▼ The effects of differential diffusion in the numerical modelling of a turbulent non-premixed hydrogen-air jet flame using a Conditional Moment Closure (CMC) method are investigated. The CMC calculations, which are coupled with computational fluid dynamics (CFD) calculations, relax the commonly used assumption of equal species mass diffusivities. The focus is on the predictions of species mass fractions and temperatures, especially the production of NO. The results of the calculations are compared with available experimental measurements. The formulation of the CMC species transport equation including differential diffusion is presented and the closure of the terms are discussed. Further, the CMC equation for conditional enthalpy is also derived in the present study. The implementation of the CMC equations using two dimensional finite volume method is discussed, including a presentation of the discretised forms of the equations. The results of the CMC calculations including the effects of differential diffusion show that NO mass fractions are increased from the large underpredictions observed for equal diffusivity results near the jet nozzle. Improvements are also found for other species such as H2 and H2O. The results show physical behaviours, such as a shift in the location of the reaction zone and increased reaction rates due to increased diffusion rates of H2. It is also found that differential diffusion effects persist downstream from the nozzle, where the effects are expected to be small, and reasons for the discrepancies are discussed in the present study. The profiles obtained from the CMC calculations show large radial variations, much larger than in equal diffusivity calculations. An analysis isolating the differential diffusion effects of various species shows that the largest changes occur due to the accounting for the differential diffusivity of H2. A budget of the terms in the CMC equations for the differentially diffusing chemical species and enthalpy is also investigated.
Subjects/Keywords: Combustion; CFD
Ma, M. C. (2014). Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame using Conditional Moment Closure Method . (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/8708
Ma, Man Ching. "Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame using Conditional Moment Closure Method." 2014. Thesis, University of Waterloo. Accessed January 19, 2021. http://hdl.handle.net/10012/8708.
Ma, Man Ching. "Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame using Conditional Moment Closure Method." 2014. Web. 19 Jan 2021.
Ma MC. Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame using Conditional Moment Closure Method. [Internet] [Thesis]. University of Waterloo; 2014. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/10012/8708.
Ma MC. Investigation of Differential Diffusion Effects in Turbulent Hydrogen Jet Flame using Conditional Moment Closure Method. [Thesis]. University of Waterloo; 2014. Available from: http://hdl.handle.net/10012/8708
10. Rajabzadeh, Amin Reza. Membrane Fouling During Hollow Fiber Ultrafiltration of Protein Solutions: Computational Fluid Modeling and Physicochemical Properties.
► Hollow fiber ultrafiltration is a viable low cost alternative technology for the concentration or separation of protein solutions. However, membrane fouling and solute build up… (more)
▼ Hollow fiber ultrafiltration is a viable low cost alternative technology for the concentration or separation of protein solutions. However, membrane fouling and solute build up in the vicinity of the membrane surface decrease the performance of the process by lowering the permeate flux. Major efforts have been devoted to study membrane fouling and design more efficient ultrafiltration membrane systems. The complexity of membrane fouling, however, has limited the progress to better understand and predict the occurrence of fouling. This work was motivated by the desire to develop a microscopic Computational Fluid Dynamics (CFD) model to capture the complexity of the membrane fouling during hollow fiber ultrafiltration of protein solutions. A CFD model was developed to investigate the transient permeate flux and protein concentration and the spatial fouling behavior during the concentration of electroacidified (pH 6) and non- electroacidified (pH 9) soy protein extracts by membrane ultrafiltration. Electroacidification of the soy protein to pH 6 was found to decrease the permeate flux during UF which resulted in longer filtration time. Lower electrostatic repulsion forces between the proteins at pH 6 (near the protein isoelectric point) resulted in a tighter protein accumulation on the membrane surface suggested to be responsible for the lower permeate flux observed in the UF of the electroacidified soy protein extract. A new transient two-component fouling resistance model based on the local pressure difference, permeate velocity and protein concentration was implemented in the resistance-in-series flux model to describe the dynamics of the reversible and irreversible fouling during the filtration and the effect of pH on the membrane fouling. Good agreement between the experimental data and the model predictions was observed. Mathematical modeling was performed to estimate the osmotic pressure and diffusion coefficient of the proteins bovine serum albumin (BSA) and soy glycinin, one of the major storage proteins in soy, as a function of protein concentration, pH, and ionic strength. Osmotic pressure and diffusion coefficient of proteins play vital roles in membrane filtration processes because they control the distribution of particles in the vicinity of the membrane surface, often influencing the permeation rate. Therefore, understanding the behavior of these properties is of great importance in addressing questions about membrane fouling. An artificial neural network was developed to analyze the estimated data in order to find a simple relation for osmotic pressure as a function of protein concentration, pH, and ionic strength. For both proteins, the osmotic pressure increased as pH diverged from the protein isoelectric point. Increasing the ionic strength, however, reversed the effect by shielding charges and thereby decreasing the osmotic pressure. Osmotic pressure of glycinin was found lower than that of BSA. Depending on how much pH was far from the isoelectric point of the protein, osmotic pressure of BSA…
Subjects/Keywords: Ultrafiltration; CFD
Rajabzadeh, A. R. (2011). Membrane Fouling During Hollow Fiber Ultrafiltration of Protein Solutions: Computational Fluid Modeling and Physicochemical Properties . (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/5786
Rajabzadeh, Amin Reza. "Membrane Fouling During Hollow Fiber Ultrafiltration of Protein Solutions: Computational Fluid Modeling and Physicochemical Properties." 2011. Thesis, University of Waterloo. Accessed January 19, 2021. http://hdl.handle.net/10012/5786.
Rajabzadeh, Amin Reza. "Membrane Fouling During Hollow Fiber Ultrafiltration of Protein Solutions: Computational Fluid Modeling and Physicochemical Properties." 2011. Web. 19 Jan 2021.
Rajabzadeh AR. Membrane Fouling During Hollow Fiber Ultrafiltration of Protein Solutions: Computational Fluid Modeling and Physicochemical Properties. [Internet] [Thesis]. University of Waterloo; 2011. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/10012/5786.
Rajabzadeh AR. Membrane Fouling During Hollow Fiber Ultrafiltration of Protein Solutions: Computational Fluid Modeling and Physicochemical Properties. [Thesis]. University of Waterloo; 2011. Available from: http://hdl.handle.net/10012/5786
11. Guan, Peizhe. CFD INVESTIGATION OF THE EFFECTS OF DPI DESIGNS AND ELECTROSTATIC CHARGES.
Degree: Materials Science & Engineering, 2017, University of New South Wales
► Interest in pharmaceutical aerosol inhalation through respiratory airway is increasing as it is a fast and effective treatment for respiratory tract diseases. Dry powder inhalers… (more)
▼ Interest in pharmaceutical aerosol inhalation through respiratory airway is increasing as it is a fast and effective treatment for respiratory tract diseases. Dry powder inhalers (DPIs) are devices containing fine pharmaceutical powders which are aerosolized during patient's inhalation and delivered into the distal part of the lung. However, existing DPIs have relatively low efficiency due to strong inter-particle cohesion caused by the small particle sizes (less than 5 microns). To improve DPI performance, both DPI devices and inter-particle forces need to be considered. This work developed a CFD model, using ANSYS Fluent to simulate the fluid flow in a commercial inhaler Aerolizer®. The Discrete Phase Modelling (DPM) technique was adopted to track particle trajectories and depositions. The aim was to investigate the effect of DPI designs and electrostatic force on powder dispersion.The particle-wall impaction has been demonstrated as the major mechanism of agglomerate breakage in DPIS. Thus, the original Aerolizer® device has been modified to add bumps inside the chamber. A series of CFD simulations were carried out to determine the effect of device design on particle dispersion performance. Sensitivity tests were conducted to examine the mesh independence of the model. The fluid flow and particle-wall impaction in the new design were compared with those in the original design. The simulation results showed that the existence of bumps directly affected the turbulence level generated in the device as it disturbed the fluid flow. This led to a reduction in the normal velocity of particle impaction and number of particle impactions. The axial velocities in mouthpieces were similar for both device designs. The fractions of particles escaped from the original device were 40%, 10% and 21% for 3 µm, 5 µm and 10 µm particles, respectively. Similarly, 55%, 47% and 22% of total particles escaped from the revised device.The electrostatic force is one of the major adhesion forces during dispersion condition in DPI. Thus, the effect of electrostatic charge on particles was investigated during dispersion condition in DPIs. The well-established charge transfer theory was employed in CFD through Fluent UDF to determine the charge condition of fine powders during dispersion. The results showed that electrostatic charge distribution for escaped particles was lower for the revised device than the original device. Due to the large difference in magnitude between the van der Waals force and electrostatic force, the electrostatic force was found to have minimal effect on the particle dispersion. The overall particle-particle impactions were not significantly affected by the electrostatic force.The study demonstrates the effects of device design and electrostatic force on particle dispersion performance providing further insight into optimising the DPI efficiency, which will provide a basis for the future improvement of DPI devices. Advisors/Committee Members: Yang, Runyu, Materials Science & Engineering, Faculty of Science, UNSW.
Subjects/Keywords: CFD; DPI
Guan, P. (2017). CFD INVESTIGATION OF THE EFFECTS OF DPI DESIGNS AND ELECTROSTATIC CHARGES . (Masters Thesis). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/58553 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46254/SOURCE02?view=true
Guan, Peizhe. "CFD INVESTIGATION OF THE EFFECTS OF DPI DESIGNS AND ELECTROSTATIC CHARGES." 2017. Masters Thesis, University of New South Wales. Accessed January 19, 2021. http://handle.unsw.edu.au/1959.4/58553 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46254/SOURCE02?view=true.
Guan, Peizhe. "CFD INVESTIGATION OF THE EFFECTS OF DPI DESIGNS AND ELECTROSTATIC CHARGES." 2017. Web. 19 Jan 2021.
Guan P. CFD INVESTIGATION OF THE EFFECTS OF DPI DESIGNS AND ELECTROSTATIC CHARGES. [Internet] [Masters thesis]. University of New South Wales; 2017. [cited 2021 Jan 19]. Available from: http://handle.unsw.edu.au/1959.4/58553 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46254/SOURCE02?view=true.
Guan P. CFD INVESTIGATION OF THE EFFECTS OF DPI DESIGNS AND ELECTROSTATIC CHARGES. [Masters Thesis]. University of New South Wales; 2017. Available from: http://handle.unsw.edu.au/1959.4/58553 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:46254/SOURCE02?view=true
12. Coenen, Roger (author). Single Skin Kite Airfoil Optimization for AWES.
Degree: 2018, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:fdcf8423-11f0-4b33-956e-3e761635ac41
► Airborne Wind Energy is a technology where wind energy is harvested with tethered flying devices. Kitepower uses flexible leading edge inflatable kites, but these have… (more)
▼ Airborne Wind Energy is a technology where wind energy is harvested with tethered flying devices. Kitepower uses flexible leading edge inflatable kites, but these have a scaling disadvantage in that they become heavier with size. A single skin kite has the potential of negating this disadvantage while at the same time being more aerodynamically efficient. An airfoil of this type is therefore investigated using Computational Fluid Dynamics and optimized using Surrogate Modelling techniques. A hybrid mesh was generated with hyperbolic extrusion and triangulation. The RANS solver that was used produced good results. The results of the optimization were unsatisfactory. The parametrization did not provide enough local control and unique airfoil shapes. The surrogate modelling approach is promising due to the computationally expensive CFD analyses. Advisors/Committee Members: Schmehl, Roland (mentor), Delft University of Technology (degree granting institution).
Subjects/Keywords: Kites; Airfoil optimisation; CFD Optimization; CFD
Coenen, R. (. (2018). Single Skin Kite Airfoil Optimization for AWES . (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:fdcf8423-11f0-4b33-956e-3e761635ac41
Coenen, Roger (author). "Single Skin Kite Airfoil Optimization for AWES." 2018. Masters Thesis, Delft University of Technology. Accessed January 19, 2021. http://resolver.tudelft.nl/uuid:fdcf8423-11f0-4b33-956e-3e761635ac41.
Coenen, Roger (author). "Single Skin Kite Airfoil Optimization for AWES." 2018. Web. 19 Jan 2021.
Coenen R(. Single Skin Kite Airfoil Optimization for AWES. [Internet] [Masters thesis]. Delft University of Technology; 2018. [cited 2021 Jan 19]. Available from: http://resolver.tudelft.nl/uuid:fdcf8423-11f0-4b33-956e-3e761635ac41.
Coenen R(. Single Skin Kite Airfoil Optimization for AWES. [Masters Thesis]. Delft University of Technology; 2018. Available from: http://resolver.tudelft.nl/uuid:fdcf8423-11f0-4b33-956e-3e761635ac41
13. Agarwal, Rahul. CFD Analysis of Effect of Viscosity and RPM on an Electrical Submersible Pump.
Degree: MS, Mechanical Engineering, 2017, Texas A&M University
► Computational fluid dynamics analysis (CFD) has been employed to study the flow behavior, and dependency of pump efficiency and head on the operating conditions of… (more)
▼ Computational fluid dynamics analysis (CFD) has been employed to study the flow behavior, and dependency of pump efficiency and head on the operating conditions of the pump and fluids pumped. Commercially available ANSYS Fluent is the tool used in this study for simulation of flow through the pump. A single stage of an ESP (Electrical submersible pump) WJE-1000, manufactured by Baker Hughes Ltd., is modeled and investigated. A three dimensional single phase flow has been considered for the numerical simulations to study pump performance, over a range of flow rates, viscosities and rotational speeds. It is shown that the pump speed does not affect the head coefficient and efficiency when plotted against flow coefficient, or in a more general sense, dimensionless parameters, when plotted against each other, are not affected by a change in rpm. Also, efficiency for all the cases can be represented on a single curve which includes flow coefficient and rotating Reynold's number. It is also shown that careful selection of the CFD model is indeed very important and more work needs to be done in that regard. The ramifications of these results are very significant. The affinity laws have been modified to include the effects of viscosity. Hence a single head coefficient curve and a single efficiency curve (power required to operate the pump) can represent the pump performance over the entire flow rate and pump speed envelop. This will allow operators to be able to predict changes in pump performance with varying fluids and pump speeds. An additional benefit is that a pump need not be tested over a wide range of fluids, but only at two viscosities in order to obtain power law coefficient on Rew. Once the relationship has been determined for a specific pump design, it can be published and utilized for all operating conditions. Advisors/Committee Members: Morrison, Gerald Lee (advisor), Pate, Michael (committee member), Kirkland, Karen Vierow (committee member).
Subjects/Keywords: ESP; CFD; Efficiency
Agarwal, R. (2017). CFD Analysis of Effect of Viscosity and RPM on an Electrical Submersible Pump . (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/161669
Agarwal, Rahul. "CFD Analysis of Effect of Viscosity and RPM on an Electrical Submersible Pump." 2017. Masters Thesis, Texas A&M University. Accessed January 19, 2021. http://hdl.handle.net/1969.1/161669.
Agarwal, Rahul. "CFD Analysis of Effect of Viscosity and RPM on an Electrical Submersible Pump." 2017. Web. 19 Jan 2021.
Agarwal R. CFD Analysis of Effect of Viscosity and RPM on an Electrical Submersible Pump. [Internet] [Masters thesis]. Texas A&M University; 2017. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1969.1/161669.
Agarwal R. CFD Analysis of Effect of Viscosity and RPM on an Electrical Submersible Pump. [Masters Thesis]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/161669
14. Tang, Yingjie. Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms.
Degree: PhD, Mechanical Engineering, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11008
► In this work, various aerosol particle transport and deposition mechanisms were studied through the computational fluid dynamics (CFD) modeling, including inertial impaction, gravitational effect, lift… (more)
▼ In this work, various aerosol particle transport and deposition mechanisms were studied through the computational fluid dynamics (CFD) modeling, including inertial impaction, gravitational effect, lift force, interception, and turbophoresis, within different practical applications including aerosol sampling inlet, filtration system and turbulent pipe flows. The objective of the research is to obtain a better understanding of the mechanisms that affect aerosol particle transport and deposition, and to determine the feasibility and accuracy of using commercial CFD tools in predicting performance of aerosol sampling devices. Flow field simulation was carried out first, and then followed by Lagrangian particle tracking to obtain the aerosol transport and deposition information. The CFD-based results were validated with experimental data and empirical correlations. In the simulation of the aerosol inlet, CFD-based penetration was in excellent agreement with experimental results, and the most significant regional particle deposition occurred due to inertial separation. At higher free wind speeds gravity had less effect on particle deposition. An empirical equation for efficiency prediction was developed considering inertial and gravitational effects, which will be useful for directing design of similar aerosol inlets. In the simulation of aerosol deposition on a screen, a "virtual surface" approach, which eliminates the need for the often-ambiguous user defined functions, was developed to account for particle deposition due to interception. The CFD-based results had a good agreement compared with experimental results, and also with published empirical correlations for interception. In the simulation of turbulent deposition in pipe flows, the relation between particle deposition velocity and wall-normal turbulent velocity fluctuation was quantitative determined for the first time, which could be used to quantify turbulent deposition, without having to carry out Lagrangian particle tracking. It suggested that the Reynolds stress model and large eddy simulation would lead to the most accurate simulated aerosol deposition velocity. The prerequisites were that the wall-adjacent y+ value was sufficiently low, and that sufficient number of prism layers was applied in the near-wall region. The "velocity fluctuation convergence" would be useful criterion for judging the adequacy of a CFD simulation for turbulent deposition. Advisors/Committee Members: Guo, Bing (advisor), Ranjan, Devesh (advisor), Chen, Hamn-Ching (committee member), Ying, Qi (committee member).
Subjects/Keywords: Aerosol; CFD; Deposition
Tang, Y. (2012). Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms . (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11008
Tang, Yingjie. "Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms." 2012. Doctoral Dissertation, Texas A&M University. Accessed January 19, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11008.
Tang, Yingjie. "Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms." 2012. Web. 19 Jan 2021.
Tang Y. Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms. [Internet] [Doctoral dissertation]. Texas A&M University; 2012. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11008.
Tang Y. Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms. [Doctoral Dissertation]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11008
15. Barnwal, Abhishek. Combustion Properties of Biologically Sourced Alternative Fuels.
Degree: 2012, University of Toronto
The effects of pressure on various properties of ten different syngas fueled flames were analyzed using one and two dimensional simulations. One-dimensional premixed flames were… (more)
The effects of pressure on various properties of ten different syngas fueled flames were analyzed using one and two dimensional simulations. One-dimensional premixed flames were modeled in CANTERA. Flame speed, adiabatic flame temperature and thermal diffusivity as functions of equivalence ratio and pressure were quantified for the fuels using four chemical kinetic mechanisms. Data from the different mechanisms displayed good agreement with data from previous experimental benchmarks. Two-dimensional axisymmetric co-flow flames were simulated in a state of the art computational framework for modeling laminar flames. Flame structure comparisons were made with past experimental and numerical results as well as with theoretical predictions. Good agreement in stoichiometric flame height was observed with past theoretical and numerical flame height measurements. Visible flame heights had little correlation with the stoichiometric flame heights. The flame radius was also noted to be proportional to p^-0.35 at high pressures instead of p^-0.5 as predicted by theory.
Advisors/Committee Members: Groth, Clinton P. T., Aerospace Science and Engineering.
Subjects/Keywords: Combustion; CFD; 0538
Barnwal, A. (2012). Combustion Properties of Biologically Sourced Alternative Fuels . (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/33332
Barnwal, Abhishek. "Combustion Properties of Biologically Sourced Alternative Fuels." 2012. Masters Thesis, University of Toronto. Accessed January 19, 2021. http://hdl.handle.net/1807/33332.
Barnwal, Abhishek. "Combustion Properties of Biologically Sourced Alternative Fuels." 2012. Web. 19 Jan 2021.
Barnwal A. Combustion Properties of Biologically Sourced Alternative Fuels. [Internet] [Masters thesis]. University of Toronto; 2012. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1807/33332.
Barnwal A. Combustion Properties of Biologically Sourced Alternative Fuels. [Masters Thesis]. University of Toronto; 2012. Available from: http://hdl.handle.net/1807/33332
16. Meier, Markus. CFD-Modellierung und Simulation von Hydrodynamik und biochemischen Prozessen in Mehrphasenströmungen.
Degree: 2015, Technische Universität Dortmund
URL: http://dx.doi.org/10.17877/DE290R-16363
► Mit der Zielsetzung die Effizienz von Belebungsbecken kommunaler Kläranlage zu steigern, wird die vollständige und systematische Kopplung eines biochemischen Modellsystems mit einer 3D-Strömungssimulationssoftware (Computational Fluid… (more)
▼ Mit der Zielsetzung die Effizienz von Belebungsbecken kommunaler Kläranlage zu steigern, wird die vollständige und systematische Kopplung eines biochemischen Modellsystems mit einer 3D-Strömungssimulationssoftware (Computational Fluid Dynamics – CFD) dargestellt. Neben der Realisierung einer Dreiphasenströmung werden anhand von Literatur- und Versuchsdaten geeignete mathematische Modelle zur Rheologie und dem Sedimentationsverhalten von Belebtschlamm entwickelt. Darauf aufbauend wird der Sauerstofftransport in die Belebtschlammsuspension systematisch modelliert und die Implementierung eines biologischen Reaktionssystems beschrieben. Neben der Simulation von Testgeometrien zur exakten Darstellung der Funktionalität, wird das Simulationsmodell ganzheitlich an experimentell aufgenommenen Konzentrationsprofilen eines realen Belebungsbeckens validiert und die Simulationsgüte mit bisher üblichen Simulationsverfahren verglichen. Die Ergebnisse zeigen, dass das entwickelte Simulationsmodell gängige Verfahren hinsichtlich der Genauigkeit übertrifft. Zur ausführlichen Untersuchung kritischer Einflussfaktoren auf das Endergebnis wird eine Sensitivitätsanalyse der wichtigsten Eingangsparameter vorgenommen. Zum Abschluss zeigen Simulationen von Verfahrensvarianten das Optimierungspotenzial des untersuchten Belebungsbeckens konsistent auf, wodurch Vorschläge zu effektiv umsetzbaren Maßnahmen unterbreitet werden. Advisors/Committee Members: Ehrhard, Peter (advisor), Wichmann, Rolf (referee).
Subjects/Keywords: CFD; Belebungsbecken; 660
Meier, M. (2015). CFD-Modellierung und Simulation von Hydrodynamik und biochemischen Prozessen in Mehrphasenströmungen . (Doctoral Dissertation). Technische Universität Dortmund. Retrieved from http://dx.doi.org/10.17877/DE290R-16363
Meier, Markus. "CFD-Modellierung und Simulation von Hydrodynamik und biochemischen Prozessen in Mehrphasenströmungen." 2015. Doctoral Dissertation, Technische Universität Dortmund. Accessed January 19, 2021. http://dx.doi.org/10.17877/DE290R-16363.
Meier, Markus. "CFD-Modellierung und Simulation von Hydrodynamik und biochemischen Prozessen in Mehrphasenströmungen." 2015. Web. 19 Jan 2021.
Meier M. CFD-Modellierung und Simulation von Hydrodynamik und biochemischen Prozessen in Mehrphasenströmungen. [Internet] [Doctoral dissertation]. Technische Universität Dortmund; 2015. [cited 2021 Jan 19]. Available from: http://dx.doi.org/10.17877/DE290R-16363.
Meier M. CFD-Modellierung und Simulation von Hydrodynamik und biochemischen Prozessen in Mehrphasenströmungen. [Doctoral Dissertation]. Technische Universität Dortmund; 2015. Available from: http://dx.doi.org/10.17877/DE290R-16363
17. Yagub, Amal Saeed. Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces.
Degree: PhD, Mechanical Engineering, 2015, Wayne State University
URL: https://digitalcommons.wayne.edu/oa_dissertations/1388
► SPECIALIZED INTER-PARTICLE INTERACTION LBM FOR PATTERNED SUPERHYDROPHOBIC SURFACES by AMAL S. YAGUB ABSTRACT: Superhydrophobic surface characteristics are important in many industrial applications, ranging from… (more)
▼ SPECIALIZED INTER-PARTICLE INTERACTION LBM FOR PATTERNED SUPERHYDROPHOBIC SURFACES by AMAL S. YAGUB ABSTRACT: Superhydrophobic surface characteristics are important in many industrial applications, ranging from the textile to the military. It was observed that surfaces fabricated with nano/micro roughness can manipulate the droplet contact angle, thus providing an opportunity to control the droplet wetting characteristics. The Shan and Chen (SC) lattice Boltzmann model (LBM) is a good numerical tool, which holds strong potentials to qualify for simulating droplets wettability. This is due to its realistic nature of droplet contact angle (CA) prediction on flat smooth surfaces. But SC-LBM was not able to replicate the CA on rough surfaces because it lacks a real representation of the physics at work under these conditions. By using a correction factor to influence the interfacial tension within the asperities, the physical forces acting on the droplet at its contact lines were mimicked. This approach allowed the model to replicate some experimentally confirmed Wenzel and Cassie wetting cases. Regular roughness structures with different spacing were used to validate the study using the classical Wenzel and Cassie equations. This work highlights the strength and weakness of the SC model and attempts to qualitatively conform it to the fundamental physics, which causes a change in the droplet apparent contact angle, when placed on nano/micro structured surfaces. In the second part of this work, the model is used also to analyze the sliding of droplets in contact with flat horizontal surfaces. This part identifies the main factors, which influence the multiphase fluids transport in squared channels. Effects of dimensionless radius, Weber number, Reynolds number and static contact angles are evaluated by calculating the power required for moving single droplets in comparison to the power needed for moving the undisturbed flow in the channel. Guidelines for optimizing the design of such flow are presented. In last part of work, the sliding of droplets on sloped surfaces with and without roughness is numerically investigated. The Shan and Chen (SC) Lattice Boltzmann model (LBM) is used to analyze the effect of pinning on the movement of droplets placed on sloped surfaces. The model is checked for conformance with the Furmidge equation which applies to tilted unstructured surfaces. It is shown that a droplet sliding on a perfectly smooth surface requires very minimal slope angle and that pinning due to the inhomogeneous nature of manufactured smooth surfaces is the key factor in determining the minimal slope angle. The model is also used on sloped rough surfaces to check the effects of roughness on the movement of single droplets. The numerical outcomes are compared with published experimental results for validation and a dimensionless number is suggested for quantifying the degree of pinning needed to control the behavior of… Advisors/Committee Members: Trilochan Singh, Hassan M. Farhat.
Subjects/Keywords: CFD; Mechanical Engineering
Yagub, A. S. (2015). Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces . (Doctoral Dissertation). Wayne State University. Retrieved from https://digitalcommons.wayne.edu/oa_dissertations/1388
Yagub, Amal Saeed. "Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces." 2015. Doctoral Dissertation, Wayne State University. Accessed January 19, 2021. https://digitalcommons.wayne.edu/oa_dissertations/1388.
Yagub, Amal Saeed. "Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces." 2015. Web. 19 Jan 2021.
Yagub AS. Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces. [Internet] [Doctoral dissertation]. Wayne State University; 2015. [cited 2021 Jan 19]. Available from: https://digitalcommons.wayne.edu/oa_dissertations/1388.
Yagub AS. Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces. [Doctoral Dissertation]. Wayne State University; 2015. Available from: https://digitalcommons.wayne.edu/oa_dissertations/1388
18. Brondolo, Luca. Comparative investigation of large eddy simulation and RANS approaches for external automotive flows.
Degree: MSc, 2011, Cranfield University
URL: http://dspace.lib.cranfield.ac.uk/handle/1826/7106
► This thesis investigates the accuracy and scalability of RANS and LES approaches applied to external automotive aerodynamics. Due to the availability of considerable experimental and… (more)
▼ This thesis investigates the accuracy and scalability of RANS and LES approaches applied to external automotive aerodynamics. Due to the availability of considerable experimental and computational data available on the Ahmed body, this reference model was chosen for this study. The relative simple geometry of the Ahmed body model is able reproduce the common flow features of a hatch back style vehicle. The 25° slant angle configuration was used as it is a major challenge in terms of flow prediction. The RANS model used included the Standard K-ε, RNG K-ε, Realizable k-ε and K-ω SST. The LES simulations were run with the Smagorinsky-Lilly SGS model. Three grids with different level of refinement were generated. A viscous hybrid mesh approach was used for all the simulations. This type of mesh is commonly used by automotive manufactures and motorsport organizations. The commercial package Fluent 12 was used as a solver. The K-ω SST and LES models showed good agreement with the experimental data. LES in particular was the only model to predict flow re-attachment over the slant angle as seen on the experimental and computational data available in literature. The richness of the unsteady data available from the LES simulations and correct interpretation of flow topology balance in part the major computational requirements compared to the RANS models. Taking into account the hardware resources available to automotive manufactures, the LES is suitable to be part of the design process.
Subjects/Keywords: Automotive; CFD; Turbulence
Brondolo, L. (2011). Comparative investigation of large eddy simulation and RANS approaches for external automotive flows . (Masters Thesis). Cranfield University. Retrieved from http://dspace.lib.cranfield.ac.uk/handle/1826/7106
Brondolo, Luca. "Comparative investigation of large eddy simulation and RANS approaches for external automotive flows." 2011. Masters Thesis, Cranfield University. Accessed January 19, 2021. http://dspace.lib.cranfield.ac.uk/handle/1826/7106.
Brondolo, Luca. "Comparative investigation of large eddy simulation and RANS approaches for external automotive flows." 2011. Web. 19 Jan 2021.
Brondolo L. Comparative investigation of large eddy simulation and RANS approaches for external automotive flows. [Internet] [Masters thesis]. Cranfield University; 2011. [cited 2021 Jan 19]. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/7106.
Brondolo L. Comparative investigation of large eddy simulation and RANS approaches for external automotive flows. [Masters Thesis]. Cranfield University; 2011. Available from: http://dspace.lib.cranfield.ac.uk/handle/1826/7106
19. Johansson, Martin. Modellering av vridspjällsventil : Skattning av egenkarakteristik och täthet.
Degree: Faculty of Technology and Science, 2011, Karlstad University
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7211
Den här rapporten undersöker hur strömningsmotståndet och tätheten i en vridspjällsventil påverkas av form på spindel och spjäll. I rapporten undersök också storleken på… (more)
Den här rapporten undersöker hur strömningsmotståndet och tätheten i en vridspjällsventil påverkas av form på spindel och spjäll. I rapporten undersök också storleken på det hydrodynamiska moment som fluiden utövar på ventilens spindel. Rapporten utgår från en referensventil som ingår i SOMAS (SOMAS Instrument AB) produktsortiment och är av typen MTV med dimensionen DN 150. Modifieringar görs på referensventilens spindel och spjäll. Som mått på strömningsmotstånd används ventilens egenkarakteristik och som mått på täthet används storleken på den elastiska deformationen på spindel och spjäll då ventilen är stängd. Kraven som ställs då spindel och spjäll modifieras är att spindeln ska vara delad, spindel och spjäll ska gå att montera in i referensventilens ventilhus och referensventilen skall vara tät då ett modifierat spjäll med delad spindel monterats in i referensventilen. För att skatta egenkarakteristik, hydrodynamiskt moment och täthet har CFD- och strukturmodeller byggts upp i COMSOL Multiphysics version 4.0a. Det har också gjorts en experimentell flödesanalys för att ta fram strömningsmotståndet på referensventilen. I examensarbetet har två modifierade spjäll med delad spindel tagits fram. De modifierade spjällen med delad spindel går att montera in i referensventilens ventilhus. CFD-analysen visar att det går att minska strömningsmotståndet i referensventilen då spjällen med delad spindel monteras in i ventilhuset. Analysen visar också att det hydrodynamiska momentet är lågt. Strukturanalysen visar att referensventilen är tät då de modifierade spjällen med delad spindel monteras in i ventilhuset.
This report investigates how design on disc and shaft affects the inherent flow characteristic and the shutoff rating on a butterfly valve. This report also investigates the size of the hydrodynamic torque acting on the shaft. Design modifications are made on a reference valve which is a butterfly valve of model MTV with dimension DN 150 and is a part of SOMAS (SOMAS Instrument AB) products. A measurement of shutoff rating is the size of the elastic deformation of the disc and the shaft. The demands of the design on disc and shaft are: the shaft will be a split type shaft, the disc and the shaft shall fit the valve body of the reference valve, the reference valve will have a shutoff rating that prevents leakage when the disc and the shaft are mounted in the body of the reference valve. To estimate the inherent flow characteristic, the hydrodynamic torque and the shutoff rating CFD-models and structural-models has been built in COMSOL Multiphysics version 4.0a. An experimental analysis has also been made to determine the inherent flow characteristic of the reference valve. This report presents two different discs with a split shaft that fits the body of the reference valve. When a newly designed disc and shaft are mounted in the body of the reference valve the CFD-analysis shows a greater inherent flow characteristic of the reference valve compared to the…
Subjects/Keywords: vridspjällsventil; CFD; strukturanalys
Johansson, M. (2011). Modellering av vridspjällsventil : Skattning av egenkarakteristik och täthet . (Thesis). Karlstad University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7211
Johansson, Martin. "Modellering av vridspjällsventil : Skattning av egenkarakteristik och täthet." 2011. Thesis, Karlstad University. Accessed January 19, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7211.
Johansson, Martin. "Modellering av vridspjällsventil : Skattning av egenkarakteristik och täthet." 2011. Web. 19 Jan 2021.
Johansson M. Modellering av vridspjällsventil : Skattning av egenkarakteristik och täthet. [Internet] [Thesis]. Karlstad University; 2011. [cited 2021 Jan 19]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7211.
Johansson M. Modellering av vridspjällsventil : Skattning av egenkarakteristik och täthet. [Thesis]. Karlstad University; 2011. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7211
20. Mitrus, Andrea. NUMERICAL INVESTIGATION OF BLADE LEADING EDGE CONTOURING BY FILLET AND BASELINE CASE OF A TURBINE VANE : A comparative study of the effect on secondary flow.
Degree: Heat and Power Technology, 2012, KTH
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98655
► The understanding of secondary flow behavior has become an important aspect in the design of modern gas turbines. Secondary flow gives rise to aerodynamic… (more)
▼ The understanding of secondary flow behavior has become an important aspect in the design of modern gas turbines. Secondary flow gives rise to aerodynamic losses, distorts the thermal field and affects the flow conditions at the exit of a passage negatively. Therefore, reducing secondary flow is a major concern for efficiency improvement. Many passive control-methods have been suggested by turbine designers and researchers, and one very promising modification is blade leading edge contouring near the endwall. At the Division of Heat and Power Technology KTH, Stockholm, a detailed experimental investigation of three filleted nozzle guide vanes in an annular sector cascade has been performed, providing excellent experimental data for numerical validation of complex turbine flows. Based on the above, a numerical study and aerodynamic investigation for a leading edge filleted vane and baseline vane has been performed. The potential effect of the leading edge fillet on flow structure and secondary losses has been evaluated based on a number of flow parameters, and computational predictions have been compared to experimental results. The numerical investigation has shown some differences in the flow behavior between the filleted and baseline case. All results indicate that the fillet affects the flow structure in regions close to the hub endwall. It shifts the position of vortices and loss core. However, the overall effect on reducing secondary losses downstream of the passage is insignificant. Additionally, the numerical results show good qualitative agreement with experimental results.
Subjects/Keywords: CFD; Secondary flow
Mitrus, A. (2012). NUMERICAL INVESTIGATION OF BLADE LEADING EDGE CONTOURING BY FILLET AND BASELINE CASE OF A TURBINE VANE : A comparative study of the effect on secondary flow . (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98655
Mitrus, Andrea. "NUMERICAL INVESTIGATION OF BLADE LEADING EDGE CONTOURING BY FILLET AND BASELINE CASE OF A TURBINE VANE : A comparative study of the effect on secondary flow." 2012. Thesis, KTH. Accessed January 19, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98655.
Mitrus, Andrea. "NUMERICAL INVESTIGATION OF BLADE LEADING EDGE CONTOURING BY FILLET AND BASELINE CASE OF A TURBINE VANE : A comparative study of the effect on secondary flow." 2012. Web. 19 Jan 2021.
Mitrus A. NUMERICAL INVESTIGATION OF BLADE LEADING EDGE CONTOURING BY FILLET AND BASELINE CASE OF A TURBINE VANE : A comparative study of the effect on secondary flow. [Internet] [Thesis]. KTH; 2012. [cited 2021 Jan 19]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98655.
Mitrus A. NUMERICAL INVESTIGATION OF BLADE LEADING EDGE CONTOURING BY FILLET AND BASELINE CASE OF A TURBINE VANE : A comparative study of the effect on secondary flow. [Thesis]. KTH; 2012. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98655
21. Bernardi, Giacomo. Feasibility Study of a 3D CFD Solution for FSI Investigations on NREL 5MW Wind Turbine Blade.
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159690
► With the increase in length of wind turbine blades flutter is becoming a potential design constrain, hence the interest in computational tools for fluid-structure… (more)
▼ With the increase in length of wind turbine blades flutter is becoming a potential design constrain, hence the interest in computational tools for fluid-structure interaction studies. The general approach to this problem makes use of simplified aerodynamic computational tools. Scope of this work is to investigate the outcomes of a 3D CFD simulation of a complete wind turbine blade, both in terms of numerical results and computational cost. The model studied is a 5MW theoretical wind turbine from NREL. The simulation was performed with ANSYS-CFX, with different volume mesh and turbulence model, in steady-state and transient mode. The convergence history and computational time was analyzed, and the pressure distribution was compared to a high fidelity numerical result of the same blade. All the model studied were about two orders of magnitude lighter than the reference in computation time, while showing comparable results in most of the cases. The results were affected more by turbulence model than mesh density, and some turbulence models did not converge to a solution. In general seems possible to obtain good results from a complete 3D CFD simulation while keeping the computational cost reasonably low. Attention should be paid to mesh quality.
Subjects/Keywords: HAWT; CFD; Aeroelasticity
Bernardi, G. (2015). Feasibility Study of a 3D CFD Solution for FSI Investigations on NREL 5MW Wind Turbine Blade . (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159690
Bernardi, Giacomo. "Feasibility Study of a 3D CFD Solution for FSI Investigations on NREL 5MW Wind Turbine Blade." 2015. Thesis, KTH. Accessed January 19, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159690.
Bernardi, Giacomo. "Feasibility Study of a 3D CFD Solution for FSI Investigations on NREL 5MW Wind Turbine Blade." 2015. Web. 19 Jan 2021.
Bernardi G. Feasibility Study of a 3D CFD Solution for FSI Investigations on NREL 5MW Wind Turbine Blade. [Internet] [Thesis]. KTH; 2015. [cited 2021 Jan 19]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159690.
Bernardi G. Feasibility Study of a 3D CFD Solution for FSI Investigations on NREL 5MW Wind Turbine Blade. [Thesis]. KTH; 2015. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159690
22. Nayak, Pratik (author). DNS study of scalar transport in a compressible turbulent jet.
URL: http://resolver.tudelft.nl/uuid:e82f94f0-f56e-4a14-a5d9-7c4c27d2d8d0
► Direct Numerical simulations (DNS) belong to the class of simulations that strive to emulate the real physical flow by trying to simulate the complete range… (more)
▼ Direct Numerical simulations (DNS) belong to the class of simulations that strive to emulate the real physical flow by trying to simulate the complete range of scales involved in the flow. Though the computational power has steadily increased in the past few decades, resolving the complete range of scales from the largest scales up to the Kolmogorov scales can be very complicated and time consuming for moderately high Reynolds numbers as well. Hence, DNS is still expected to be a research tool to study relatively simple flows and geometries for the forseeable future unlike its counterparts such as Large Eddy Simulations (LES) and Reynolds Averaged Navier – Stokes (RANS) methods. The main objective of DNS studies is to study the flows so that turbulence models which are parametrized can be improved upon with the physical insight from the results of DNS. It also helps in studying the effect of numerical methods and techniques applicable to real flows and their stand-alone effects without any type of modeling as done for LES or RANS. This thesis is concerned with the DNS study of a compressible turbulent jet. A turbulent jet belongs to the class of free turbulent flows, in the sense that, it is not bounded physically. In this thesis, the transport of a passive scalar through the jet is studied. At higher Reynolds numbers, for convection dominated equations such as the scalar transport equation, discontinuities can occur due to the hyperbolic nature of the equations. When central methods are used, oscillations are observed in the regions of the discontinuities. These oscillations can make the solution unphysical. Therefore, in this thesis the scalar transport equation has been modeled with an additional Weighted Essentially Non-Oscillatory (WENO) interpolation to accurately capture the discontinuities without oscillations. The WENO interpolation is combined with central compact finite difference methods to reduce the numerical dissipation while maintaining the order of accuracy in the smooth regions which is essential in high Reynolds number flows. It was observed that a high dissipation setting for the WENO interpolation removed the oscillations but introduced artificial numerical viscosity. Therefore a relatively large domain was used with a low dissipation which while removing the oscillations and reducing the numerical dissipation. The WENO method for the compressible turbulent jet was first validated with experimental results to ascertain the accuracy of the grid resolution. The same grid resolution was used to study some properties of the jet at two different Schmidt numbers at a slightly lower Reynolds number. It was observed that the results obtained with the WENO interpolation matched well with the experimental results while being physical valid solutions because they had no oscillations. The results also showed different modes of instabilities for different Schmidt numbers and that the decay rate is a good characterization of the properties of the turbulent jet. In conclusion, the… Advisors/Committee Members: Boersma, Bendiks Jan (mentor), Delft University of Technology (degree granting institution).
Subjects/Keywords: CFD; DNS; Turbulence
Nayak, P. (. (2017). DNS study of scalar transport in a compressible turbulent jet . (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:e82f94f0-f56e-4a14-a5d9-7c4c27d2d8d0
Nayak, Pratik (author). "DNS study of scalar transport in a compressible turbulent jet." 2017. Masters Thesis, Delft University of Technology. Accessed January 19, 2021. http://resolver.tudelft.nl/uuid:e82f94f0-f56e-4a14-a5d9-7c4c27d2d8d0.
Nayak, Pratik (author). "DNS study of scalar transport in a compressible turbulent jet." 2017. Web. 19 Jan 2021.
Nayak P(. DNS study of scalar transport in a compressible turbulent jet. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Jan 19]. Available from: http://resolver.tudelft.nl/uuid:e82f94f0-f56e-4a14-a5d9-7c4c27d2d8d0.
Nayak P(. DNS study of scalar transport in a compressible turbulent jet. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:e82f94f0-f56e-4a14-a5d9-7c4c27d2d8d0
23. Liang, X. (author). Numerical Study of Flow around Bypass Pigs.
URL: http://resolver.tudelft.nl/uuid:632afd2e-81de-42e3-a25e-3e2d4eb1aad4
► In the oil and gas industry, pipeline networks are used to transport the production fluids from wells to production plants. During normal operation, the pipelines… (more)
▼ In the oil and gas industry, pipeline networks are used to transport the production fluids from wells to production plants. During normal operation, the pipelines need regular cleaning and inspection. Typically, the pipeline maintenance is performed by pigging, which refers to using devices known as "pigs "(Pipeline Inspection Gauges) to perform various maintenance operations of the pipeline. In order to describe the motion of the pig in the pipeline, detailed understanding of the flow around the pig is required. In this research, a CFD (computational fluid dynamics) approach was applied to model fully turbulent flow (Re ¼ 107) around various types of bypass pigs. We especially focused on the relation between the overall pressure drop, which was represented by a dimensionless pressure loss coefficient, and various dimensionless parameters describing the flow and the configuration. The pressure loss coefficient is caused by the fluid that passes through the bypass area. If the pressure loss coefficient is known, together with the friction between the moving pig and the pipe wall, the motion of the pig can be described. Moreover, often the flow in the pipeline is in multiphase (stratified flow) condition. Therefore, in this research the effect of multiphase flow around a bypass pig was also investigated. For the single phase study, two types of bypass pigs were investigated: the disk pig and the complex bypass pig. The disk pig has a fixed and relatively simple geometry, and it is based on the conventional bypass pig, with a deflector plate in front of the pig body. The complex bypass pig geometry is based on the disk pig, though now the bypass area is created by holes which can be adjusted. In reality, for these complex bypass pigs, the bypass pig velocity is controlled by adjusting the bypass area. For the conventional bypass pig, previous studies have shown that the Idelchik's correlation for thick orifices can predict the pressure loss coefficient accurately. Thus a similar approach was applied in the disk pig study in order to obtain a theoretical correlation to predict the pressure loss coefficient for the disk pig. Indeed such a correlation was found which gives an accurate prediction for a certain parameter regime. In the complex bypass pig study, we mainly focused on the influence of the bypass area fraction on the pressure loss coefficient. Two correlations based on two approaches were suggested. It was found that these correlations can predict the overall pressure drop across the complex bypass pig accurately, especially when the opening fraction of the bypass adjusting holes was relatively large. Furthermore, for the multiphase study, the simpler pig models were investigated. First of all, the flow in front of a pig without bypass region was investigated. One of the practical purposes of this study is that we want to investigate under which condition the full pipeline perimeter gets wetted with liquid. This is important for the distribution of corrosion inhibitors. Moreover, the multiphase flow around a… Advisors/Committee Members: Henkes, R.A.W.M. (mentor), Breugem, W.P. (mentor), Hendrix, M.H.W. (mentor).
Subjects/Keywords: CFD; Bypass pig
Liang, X. (. (2015). Numerical Study of Flow around Bypass Pigs . (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:632afd2e-81de-42e3-a25e-3e2d4eb1aad4
Liang, X (author). "Numerical Study of Flow around Bypass Pigs." 2015. Masters Thesis, Delft University of Technology. Accessed January 19, 2021. http://resolver.tudelft.nl/uuid:632afd2e-81de-42e3-a25e-3e2d4eb1aad4.
Liang, X (author). "Numerical Study of Flow around Bypass Pigs." 2015. Web. 19 Jan 2021.
Liang X(. Numerical Study of Flow around Bypass Pigs. [Internet] [Masters thesis]. Delft University of Technology; 2015. [cited 2021 Jan 19]. Available from: http://resolver.tudelft.nl/uuid:632afd2e-81de-42e3-a25e-3e2d4eb1aad4.
Liang X(. Numerical Study of Flow around Bypass Pigs. [Masters Thesis]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:632afd2e-81de-42e3-a25e-3e2d4eb1aad4
24. Wang, Ran. NUMERICAL SIMULATIONS ON FLOW AROUND AN INCLINED CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBER.
Degree: MA, Civil and Environmental Engineering, 2018, University of Windsor
URL: https://scholar.uwindsor.ca/etd/7584
► Existing studies suggested a number of possible contributing factors to dry inclined cable galloping, including the axial flow forming on the leeward side of the… (more)
▼ Existing studies suggested a number of possible contributing factors to dry inclined cable galloping, including the axial flow forming on the leeward side of the inclined cable and the emergence of critical Reynolds number. The current study aims at investigating the role of cylinder orientation and Reynolds number in this phenomenon. A combination of the detached eddy and large eddy simulations was conducted to study the fluid structure around and aerodynamic force coefficients of a stationary circular cylinder normal to or inclined against the oncoming flow. The developed numerical models have been validated using existing numerical and experimental data. The effect of axial flow, in terms of the cylinder orientation represented by the attack angle (0 ◦ , 30 ◦ , 45 ◦ , 60 ◦ ), and the Reynolds number (3900, 1.4E4 , 1E5 , 1.4E5 , 2.8E5 ) have been discussed in detailed. A numerical study has been performed to indirectly examine the effect of the axial flow via a perforated splitter plate. Visualization of the fluid structure shows that a secondary flow forms on the leeward side of the circular cylinder when it is inclined, and the separated shear flow becomes more stable as cylinder orientation increases. Results indicate that the inclination of the circular cylinder would cause a near-zero span-wise averaged lift force due to the span-wise delay of the sectional cross-flow force coefficient. The sectional lift force coefficient is found to become more disorganized when the flow enters the critical Reynolds number régime in general. Within this critical range, the span-wise averaged lift force coefficient shows a peak amplitude that significantly differs from that in the subsequent shedding cycles when the attack angle is less than 45 ◦ . Results of the perforated splitter plate manifest that with the decrease of the splitter plate perforation ratio, a stronger interruption on the interaction between the two separated shear flows was found. Advisors/Committee Members: Cheng, Shaohong, Ting, David S-K..
Subjects/Keywords: CFD; Galloping; OpenFOAM
Wang, R. (2018). NUMERICAL SIMULATIONS ON FLOW AROUND AN INCLINED CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBER . (Masters Thesis). University of Windsor. Retrieved from https://scholar.uwindsor.ca/etd/7584
Wang, Ran. "NUMERICAL SIMULATIONS ON FLOW AROUND AN INCLINED CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBER." 2018. Masters Thesis, University of Windsor. Accessed January 19, 2021. https://scholar.uwindsor.ca/etd/7584.
Wang, Ran. "NUMERICAL SIMULATIONS ON FLOW AROUND AN INCLINED CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBER." 2018. Web. 19 Jan 2021.
Wang R. NUMERICAL SIMULATIONS ON FLOW AROUND AN INCLINED CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBER. [Internet] [Masters thesis]. University of Windsor; 2018. [cited 2021 Jan 19]. Available from: https://scholar.uwindsor.ca/etd/7584.
Wang R. NUMERICAL SIMULATIONS ON FLOW AROUND AN INCLINED CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBER. [Masters Thesis]. University of Windsor; 2018. Available from: https://scholar.uwindsor.ca/etd/7584
25. He, Gongqiang. Applications of CFD Simulations on Fractal Fluid Distributor.
Degree: MSChE, Chemical Engineering, 2015, Louisiana State University
URL: etd-03252015-125953 ; https://digitalcommons.lsu.edu/gradschool_theses/293
► Since its emergence in 1970s, process intensification has been attracting extensive research interests from both academic and industrial societies over the years. One good example… (more)
▼ Since its emergence in 1970s, process intensification has been attracting extensive research interests from both academic and industrial societies over the years. One good example of process intensification in chemical industry is the optimization of flow distributors. In many chemical processes, the uniformity of flow distributions plays the key role in determining the overall efficiency. Conventional distributors rely on high pressure drop to achieve acceptable flow distribution. With scaling symmetry from fractal, fractal distributors can handle fluid distribution much better than conventional distributors. With the rapid development of computation power and numerical simulation algorithms, Computer Fluid Dynamics (CFD) provides us a better understanding of physics in chemical industries. This thesis is seeking to achieve process intensification by designing a novel ion-exchanger with fractal distributor. Residence time distribution test has been conducted to study the design of fractal distributor. CFD simulations help to gain insights on fluid flow inside the device and offers optimization on fractal distributor for flow distribution uniformity. Coefficient of Variation has been used to estimate distributor performance.
Subjects/Keywords: fractal; distributor; CFD
He, G. (2015). Applications of CFD Simulations on Fractal Fluid Distributor . (Masters Thesis). Louisiana State University. Retrieved from etd-03252015-125953 ; https://digitalcommons.lsu.edu/gradschool_theses/293
He, Gongqiang. "Applications of CFD Simulations on Fractal Fluid Distributor." 2015. Masters Thesis, Louisiana State University. Accessed January 19, 2021. etd-03252015-125953 ; https://digitalcommons.lsu.edu/gradschool_theses/293.
He, Gongqiang. "Applications of CFD Simulations on Fractal Fluid Distributor." 2015. Web. 19 Jan 2021.
He G. Applications of CFD Simulations on Fractal Fluid Distributor. [Internet] [Masters thesis]. Louisiana State University; 2015. [cited 2021 Jan 19]. Available from: etd-03252015-125953 ; https://digitalcommons.lsu.edu/gradschool_theses/293.
He G. Applications of CFD Simulations on Fractal Fluid Distributor. [Masters Thesis]. Louisiana State University; 2015. Available from: etd-03252015-125953 ; https://digitalcommons.lsu.edu/gradschool_theses/293
26. Ayeni, Oladapo Olanrewaju. Sedimentation of swarms of particles at low and moderate Reynolds numbers.
URL: etd-07022013-191335 ; https://digitalcommons.lsu.edu/gradschool_theses/1210
► The sedimentation of a cloud of particles in a viscous fluid at low and moderate Reynolds numbers has been studied using an Eulerian-Lagrangian multiphase flow… (more)
▼ The sedimentation of a cloud of particles in a viscous fluid at low and moderate Reynolds numbers has been studied using an Eulerian-Lagrangian multiphase flow approach. We looked at the volume fraction dependence of the settling cloud and find a similar dependence in the simulations as in the theoretical predictions of (Nitsche and Batchelor 1997). The average cloud settling velocity and the velocity fluctuations around this average are found to have a functional dependence on ö1/3 at negligible Reynolds number. The velocity fluctuations display strong anisotropy with the magnitude of the vertical component almost three times the magnitude of the horizontal component. Similarities in the interaction between a system of two particle clouds and a system of two immiscible droplets was established with an observed increase in the velocity of the trailing cloud due to drag reduction in the wake of the leading cloud. The formation of the stagnation points at the leading front of the cloud is pointed to as the cause of shape deformation in these systems. Particle leakage at low Reynolds number was established and found to be directly related to the initial number of particles At higher Reynolds numbers, the cloud of particles evolved into an open torus and subsequently losing its axi-symmetry and breaking-up into a number of secondary clouds. This process is a type of Rayleigh-Taylor instability and the number of secondary drops was found in our simulations to be dependent on the shape of the boundaries of the flow domain used rather than the nature of the boundaries. Breakup at moderate Rec is found to occur after a critical aspect ratio is reached and a scaling was proposed for dependence of the breakup length and breakup time on Rec.
Subjects/Keywords: Instability; DPM; CFD
Ayeni, O. O. (2013). Sedimentation of swarms of particles at low and moderate Reynolds numbers . (Masters Thesis). Louisiana State University. Retrieved from etd-07022013-191335 ; https://digitalcommons.lsu.edu/gradschool_theses/1210
Ayeni, Oladapo Olanrewaju. "Sedimentation of swarms of particles at low and moderate Reynolds numbers." 2013. Masters Thesis, Louisiana State University. Accessed January 19, 2021. etd-07022013-191335 ; https://digitalcommons.lsu.edu/gradschool_theses/1210.
Ayeni, Oladapo Olanrewaju. "Sedimentation of swarms of particles at low and moderate Reynolds numbers." 2013. Web. 19 Jan 2021.
Ayeni OO. Sedimentation of swarms of particles at low and moderate Reynolds numbers. [Internet] [Masters thesis]. Louisiana State University; 2013. [cited 2021 Jan 19]. Available from: etd-07022013-191335 ; https://digitalcommons.lsu.edu/gradschool_theses/1210.
Ayeni OO. Sedimentation of swarms of particles at low and moderate Reynolds numbers. [Masters Thesis]. Louisiana State University; 2013. Available from: etd-07022013-191335 ; https://digitalcommons.lsu.edu/gradschool_theses/1210
27. Kremer, Réan. CFD Analysis of a Sailing Ship in Quartering Waves .
Degree: Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper, 2020, Chalmers University of Technology
URL: http://hdl.handle.net/20.500.12380/301691
► Predicting the motions of a ship in waves has traditionally been done using methods based on potential theory. However, these methods are limited in the… (more)
▼ Predicting the motions of a ship in waves has traditionally been done using methods based on potential theory. However, these methods are limited in the phenomena they can take into account and the level of information they produce. In these cases CFD can play an important role. In this report a CFD program called ReFRESCO is used to study the motion and force response of a ship sailing in regular quartering waves with 6 degrees of freedom. The ship in question is the KRISO container ship (KCS). First the necessary methodology is developed by incrementally increasing the number of degrees of freedom for a ship in bow quartering waves. The drift problem that is associated with surge, sway and yaw motion is solved by using conceptual spring models. Once a methodology is found, it is applied to a number of different cases with varying wave frequencies and amplitudes, both in stern and bow quartering seas. It is concluded that this method predicts the ship motion and surge force with reasonable accuracy. The forces in sway and yaw are also investigated, though no validation can be done as no experimental data is obtainable for comparison.
Subjects/Keywords: CFD; Seakeeping; Ships
Kremer, R. (2020). CFD Analysis of a Sailing Ship in Quartering Waves . (Thesis). Chalmers University of Technology. Retrieved from http://hdl.handle.net/20.500.12380/301691
Kremer, Réan. "CFD Analysis of a Sailing Ship in Quartering Waves ." 2020. Thesis, Chalmers University of Technology. Accessed January 19, 2021. http://hdl.handle.net/20.500.12380/301691.
Kremer, Réan. "CFD Analysis of a Sailing Ship in Quartering Waves ." 2020. Web. 19 Jan 2021.
Kremer R. CFD Analysis of a Sailing Ship in Quartering Waves . [Internet] [Thesis]. Chalmers University of Technology; 2020. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/20.500.12380/301691.
Kremer R. CFD Analysis of a Sailing Ship in Quartering Waves . [Thesis]. Chalmers University of Technology; 2020. Available from: http://hdl.handle.net/20.500.12380/301691
28. Coe, Ryan Geoffrey. Improved Underwater Vehicle Control and Maneuvering Analysis with Computational Fluid Dynamics Simulations.
Degree: PhD, Aerospace Engineering, 2013, Virginia Tech
► The quasi-steady state-space models generally used to simulate the dynamics of underwater vehicles perform well in most steady flow scenarios, and are therefore acceptable for… (more)
▼ The quasi-steady state-space models generally used to simulate the dynamics of underwater vehicles perform well in most steady flow scenarios, and are therefore acceptable for modeling today\'s fleet of endurance-focused autonomous underwater vehicles (AUVs). However, with their usage of numerous assumptions and simplifications, these models are not well suited to certain unsteady flow situations and for use in the development of AUVs capable of performing more extreme maneuvers. In the interest of better serving efforts to design a new generation of more maneuverable AUVs, a tool for simulating vehicle maneuvering within computational fluid dynamics (CFD) based environments has been developed. Unsteady Reynolds-averaged Navier-Stokes (URANS) simulations are used in conjunction with a 6-degree-of-freedom (6-DoF) rigid-body kinematic model to provide a numerical test basin for vehicle maneuvering simulations. The accuracy of this approach is characterized through comparison with experimental measurements and quasi-steady state-space models. Three state-space models are considered: one model obtained from semi-empirical database regression (this is the method most commonly used in application) and two models populated with coefficients determined from the results of prescribed motion CFD simulations. CFD analyses focused on supporting the design of a general purpose AUV are also presented. Advisors/Committee Members: Neu, Wayne L. (committeechair), Tafti, Danesh K. (committee member), Stilwell, Daniel J. (committee member), Woolsey, Craig A. (committee member).
Subjects/Keywords: CFD; AUV; Maneuvering
Coe, R. G. (2013). Improved Underwater Vehicle Control and Maneuvering Analysis with Computational Fluid Dynamics Simulations . (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/23777
Coe, Ryan Geoffrey. "Improved Underwater Vehicle Control and Maneuvering Analysis with Computational Fluid Dynamics Simulations." 2013. Doctoral Dissertation, Virginia Tech. Accessed January 19, 2021. http://hdl.handle.net/10919/23777.
Coe, Ryan Geoffrey. "Improved Underwater Vehicle Control and Maneuvering Analysis with Computational Fluid Dynamics Simulations." 2013. Web. 19 Jan 2021.
Coe RG. Improved Underwater Vehicle Control and Maneuvering Analysis with Computational Fluid Dynamics Simulations. [Internet] [Doctoral dissertation]. Virginia Tech; 2013. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/10919/23777.
Coe RG. Improved Underwater Vehicle Control and Maneuvering Analysis with Computational Fluid Dynamics Simulations. [Doctoral Dissertation]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/23777
29. Chen, Yan. Numerical simulation of the aerodynamic performance of an H-rotor.
Degree: MS, 2011, University of Louisville
URL: 10.18297/etd/237 ; https://ir.library.louisville.edu/etd/237
► Vertical axis wind turbines (VAWTs) are devices to convert wind energy into electricity. Unlike horizontal axis wind turbines (HAWT) where the main rotor shaft is… (more)
▼ Vertical axis wind turbines (VAWTs) are devices to convert wind energy into electricity. Unlike horizontal axis wind turbines (HAWT) where the main rotor shaft is set horizontally, VAWTs use vertical rotor shaft. Unlike HAWTs, VAWTs can be effectively used in urban environment where flow is characterized with unsteadiness and turbulence. The efficiency of the VA WTs highly depends on the aerodynamics of the wind blades. In this thesis we study the aerodynamics of the H-rotor, one type of VAWTs using computational fluid dynamics methods. Two different approaches are used in this study. One is based on direct numerical simulation (DNS) method and another is based on Reynolds averaged Navier-Stoke (RANS) model. For DNS study we solve the incompressible Navier-Stokes equations with a CFD package, OVERTURE. An overlapping moving grids technique is employed to handle the rotation of the wind turbine. For RANS simulation we used a commercial CFD package ANSYS-Fluent. The sliding mesh model of ANSYS-Fluent is applied to evaluate unsteady interaction between the stationary and rotating components. Our simulation shows that the DNS cannot correctly predict the power coefficient due to the lack of grid resolution at high Reynolds numbers. The RANS simulation results closely match the experimental data and RANS provides a way to study wind turbine aerodynamics in an efficient and reliable manner. Our simulation shows that the rotor with NACA0015 blade section obtains a maximum power coefficient of 0.16 at tip speed ratio of 2.5 for mean wind velocity of 3.9m/s. By replacing the blade section with NACA0022 airfoil profile, the maximum power coefficient of the rotor can be improved to 0.21 at tip speed ratio of 2.5 in the same wind conditions. Advisors/Committee Members: Lian, Yongsheng.
Subjects/Keywords: CFD; H-rotor
Chen, Y. (2011). Numerical simulation of the aerodynamic performance of an H-rotor. (Masters Thesis). University of Louisville. Retrieved from 10.18297/etd/237 ; https://ir.library.louisville.edu/etd/237
Chen, Yan. "Numerical simulation of the aerodynamic performance of an H-rotor." 2011. Masters Thesis, University of Louisville. Accessed January 19, 2021. 10.18297/etd/237 ; https://ir.library.louisville.edu/etd/237.
Chen, Yan. "Numerical simulation of the aerodynamic performance of an H-rotor." 2011. Web. 19 Jan 2021.
Chen Y. Numerical simulation of the aerodynamic performance of an H-rotor. [Internet] [Masters thesis]. University of Louisville; 2011. [cited 2021 Jan 19]. Available from: 10.18297/etd/237 ; https://ir.library.louisville.edu/etd/237.
Chen Y. Numerical simulation of the aerodynamic performance of an H-rotor. [Masters Thesis]. University of Louisville; 2011. Available from: 10.18297/etd/237 ; https://ir.library.louisville.edu/etd/237
30. Choudhury, Rishabh. Global Surface Temperature Measurement for Hypersonic Flight Vehicles.
Degree: Engineering & Information Technology, 2014, University of New South Wales
► This dissertation describes the use of permanent-change thermal paints as a technique for global surface temperature measurements on short-duration hypersonic flight vehicles. The thermal paints… (more)
▼ This dissertation describes the use of permanent-change thermal paints as a technique for global surface temperature measurements on short-duration hypersonic flight vehicles. The thermal paints provide an inexpensive, robust and relatively quick way of instrumenting hypersonic flight vehicles to measure in-flight surface temperatures through a single or multiple colour change which is a function of both the soak temperature and exposure time. A lack of quantitative surface temperature measurement for hypersonic flights through the use of this technique was found in the existing literature. The colour-change dependency on the exposed temperature history necessitated the transient calibration of these thermal paints. An experimental rig capable of replicating the time-varying high temperatures encountered during the short-duration hypersonic flights has been designed and developed using an electric-arc based method as a part of this work. This enabled the calibration of the thermal paints for theuse during hypersonic flight tests. Permanent-change thermal paints were used on the USAF/DSTO HIFiRE-0 hypersonic test vehicle as an initial test to measure the heating distribution for a suborbital parabolic flight trajectory. Post-flight recovery of the flight vehicle indicated that the patches of the thermal paints applied on the patch antenna section of the aluminium instrumentation can had undergone a visible colour change due toin-flight heating. The calibration of the same thermal paints was performed using the electric-arc based system which reproduced the predicted surface temperature histories obtained from the numerical conjugate-heat-transfer simulations. The numerical code and methodology used during this work to predict the surface temperature histories of the hypersonic flight vehicles was validated using in-flight data available from the HIFiRE-1 hypersonic flight test. The colour-change of the thermal paints for both the recovered flight and the calibrated samples were quantified andcompared using spectral and image analysis. The comparison provided a good agreement between the two sets of data and a quantitative surface temperature map of the patch antenna at the end of the descent phase of the HIFiRE-0 flight vehicle was deduced using the calibration data. The accuracy and the ambient pressure dependence of the thermal paints have also been discussed in this work. Advisors/Committee Members: Neely, Andrew, Engineering & Information Technology, UNSW Canberra, UNSW.
Subjects/Keywords: CFD; hypersonics; HIFiRE
Choudhury, R. (2014). Global Surface Temperature Measurement for Hypersonic Flight Vehicles . (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/53818 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12517/SOURCE02?view=true
Choudhury, Rishabh. "Global Surface Temperature Measurement for Hypersonic Flight Vehicles." 2014. Doctoral Dissertation, University of New South Wales. Accessed January 19, 2021. http://handle.unsw.edu.au/1959.4/53818 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12517/SOURCE02?view=true.
Choudhury, Rishabh. "Global Surface Temperature Measurement for Hypersonic Flight Vehicles." 2014. Web. 19 Jan 2021.
Choudhury R. Global Surface Temperature Measurement for Hypersonic Flight Vehicles. [Internet] [Doctoral dissertation]. University of New South Wales; 2014. [cited 2021 Jan 19]. Available from: http://handle.unsw.edu.au/1959.4/53818 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12517/SOURCE02?view=true.
Choudhury R. Global Surface Temperature Measurement for Hypersonic Flight Vehicles. [Doctoral Dissertation]. University of New South Wales; 2014. Available from: http://handle.unsw.edu.au/1959.4/53818 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:12517/SOURCE02?view=true