Compressibility and wall-cooling effects on high-speed turbulent boundary layers

Flight systems operating at high speeds are frequently enveloped by turbulent, hot, highly compressible flow experiencing various regimes in terms of Mach numbers and surface temperature. These factors are dominant in the proximity of the surface, the boundary layer, posing technical difficulties in predicting the mechanical and thermal loads. In this work, we analyze a database of Direct numerical Simulations of turbulent boundary layers for Mach numbers 2, 4 and 6 and four different wall temperatures (from adiabatic to cold wall). We discuss the choice of the diabatic parameter to define the degree of wall-cooling across different Mach numbers, observing its influence on instantaneous fields and first-second order velocity and temperature statistics.