Compressible flow geometric porosity modeling and spacecraft parachute computation with isogeometric discretization
One of the challenges in computational fluid structure interaction (FSI) analysis of spacecraft parachutes is the "geometric porosity," a design feature created by the hundreds of gaps and slits that the flow goes through. Because FSI analysis with resolved geometric porosity would be exceedingly time consuming, accurate geometric porosity modeling becomes essential. The geometric porosity model introduced earlier in conjunction with the space time FSI method enabled successful computational analysis and design studies of the Orion spacecraft parachutes in the incompressible flow regime. Recently, porosity models and ST computational methods were introduced, in the context of finite element discretization, for compressible flow aerodynamics of parachutes with geometric porosity. The key new component of the ST computational framework was the compressible flow ST slip interface method, introduced in conjunction with the compressible flow ST SUPG method. Here, we integrate these porosity models and ST computational methods with isogeometric discretization. We use quadratic NURBS basis functions in the computations reported. This gives us a parachute shape that is smoother than what we get from a typical finite element discretization. In the flow analysis, the combination of the ST framework, NURBS basis functions, and the SUPG stabilization assures superior computational accuracy. The computations we present for a drogue parachute show the effectiveness of the porosity models, ST computational methods, and the integration with isogeometric discretization.