Numerical Investigation of Hypersonic Turbulence Transition Delay via Porous Walls*

The present abstract outlines the progress made towards conducting a numerical analysis using direct numerical simulation (DNS) of transition to turbulence in a hypersonic boundary layer over a cone which include the effects of acoustic energy absorption by a porous insert at the conical surface. A previous experimental study by Wagner et al. Exp. Fluids (2013) showed the capability of carbon/carbon (C/C) ultrasonically absorptive porous surfaces of performing a hypersonic boundary layer transition delay. The current numerical study uses the same flow conditions to compare the transition control obtained via the modelling the carbon/carbon (C/C) acoustic response as a complex impedance boundary condition (IBC) to the experimental results. To accurately model a fully anisotropic material such as C/C a new acoustic model was developed based on experimental results of pore size distribution.