TRANSONIC SHOCKWAVE TURBULENT BOUNDARY-LAYER INTERACTIONS ON A POROUSSURFACE

Transonic shockwave/turbulent boundary layer interactions on a porous surface above a closed plenum chamber have been studied experimentally in the choked flow of a windtunnel test-section. The equivalent frees tream Mach number is 0.76 and results were obtained for three shock st rengths. Without the porous surface the Mach numbers ahead of the shoc k were 1.13, 1.18 and 1.26. The respective shock Mach numbers with the porous surface were 1.10, 1.11 and 1.19. Laser holographic interferom etry results are used to measure the density flowfield and examine the nature of the interaction. These results show that the interaction on the porous surface is modified by a thin shear layer adjacent to the surface and the weakening of the shockwave is attributed to this. The interaction was also studied by solving the two-dimensional Reynolds-a veraged Navier-Stokes equations together with the two-layer algebraic eddy-viscosity model of Baldwin-Lomax modified with appropriate correc tions for surface transpiration. The computed results show excellent a greement with the experimental data. The examination of these numerica l results shows that the surface transpiration occurs at a low subsoni c velocity and suggests that the effect of the transpiration through t he porous surface on the interaction may be optimised.