Blasius boundary layer  In physics and fluid mechanics, a Blasius boundary layer (named after Paul Richard Heinrich Blasius) describes the steady two-dimensional laminar boundary layer that forms on a semi-infinite plate which is held parallel to a constant unidirectional flow. Falkner and Skan later generalized Blasius' solution to wedge flow (Falkner–Skan boundary layer), i.e. flows in which the plate is not parallel to the flow. Using scaling arguments, Ludwig Prandtl has argued that about half of the terms in the Navier-Stokes equations are negligible in boundary layer flows (except in a small region near the leading edge of the plate). This leads to a reduced set of equations known as the boundary layer equations. For steady incompressible flow with constant viscosity and density, these read:  Continuity: formula_1  formula_2-Momentum: formula_3  formula_4-Momentum: formula_5  Here the coordinate system is chosen with formula_2 pointing parallel to the plate in the direction of the flow and the formula_4 coordinate pointing towards the free stream, formula_8 and formula_9 are the formula_2 and formula_4 velocity components, formula_12 is the pressure, formula_13 is the density and formula_14 is the kinematic viscosity. The formula_4-momentum equation implies that the pressure in the boundary layer must be equal to that of the free stream for any given formula_2 coordinate. Because the velocity profile is uniform in the free stream, there is no vorticity involved, therefore a simple Bernoulli's equation can be applied in this high Reynolds number limit formula_17 constant or, after differentiation: formula_18 Here formula_19 is the velocity of the fluid outside the boundary layer and is solution of Euler equations (fluid dynamics). Von Kármán Momentum integral and the energy integral for Blasius profile reduce to  where formula_22 is the wall shear stress, formula_23 is the wall injection/suction velocity, formula_24 is the energy dissipation rate, formula_25 is the momentum thickness and formula_26 is the energy thickness. A number of similarity solutions to this equation have been found for various types of flow, including flat plate boundary layers. The term "similarity" refers to the property that the velocity profiles at different positions in the flow are the same apart from a scaling factor.