Direct Numerical Simulation of Film Cooling in Hypersonic Boundary-Layer Flow

Effusion cooling by discrete slits and holes in various laminar zero-pressure gradient super- and hypersonic boundary layers is investigated using direct numerical simulation for an adiabatic Mach-6 boundary layer it was found that slits are better than holes due to the lower blowing velocity. Slit blowing causes a destabilisation of 2(nd)-mode disturbances, and a complete stabilization of 1(st) modes despite the generated maxima of the spanwise vorticity inside the boundary layer. Hole blowing gives rise to counter rotating steamwise vortices, with a noticeable laminar-flow destabilisation only for large spanwise hole spacings. Computation aspects such as the performance of the numberical code on the supercomputer NEC SX-8 and optimization of the code are also discussed.