Effect of short regions of surface curvature on compressible turbulent boundary layers

Calculations were performed to investigate the supersonic flow of a turbulent boundary layer over short regions of concave surface curvature. The freestream Mach number was 2.9 upstream of each curved surface. Three different constant radii of curvature wind-tunnel models were investigated to cover a range of curvature and turning angles. The numerical technique solved the full, Reynolds-averaged Navier-Stokes equations using two different turbulence models: an algebraic eddy-viscosity model, and a one-equation model. The calculations were compared with recent experimental data, and the agreement with the mean-flow results was surprisingly good, especially for the computations using the one-equation model. The computed Reynolds shear stress results tended to fall below the experimental values as the radius of curvature decreased, demonstrating the shortcomings of the turbulence models for rapidly perturbed flows. Some limiting cases for zero radius of curvature (compression corner flows) were also investigated, and the results appear to show a periodic unsteadiness similar to that observed in recent experiments.