DNS of Transition to Turbulence in a Hypersonic Boundary Layer

摘要

We perform direct numerical simulations (DNS) of transition to turbulence in a hypersonic boundary layer flow. The flow conditions correspond to a Mach 6, cold-wall flow with a wall temperature to adiabatic temperature ratio (T_w/T_(aw)) of around 0.16. The momentum thickness Reynolds number Reg goes up to around 6000 at the end of the computed turbulent zone. Comparisons are made to empirical skin-friction and heat transfer coefficients. We find that the Van Driest Ⅱ and Eckert correlations work best along with a Reynolds Analogy Factor of ≈ 1.2. Statistics from the mean and fluctuating turbulent flow fields are briefly discussed. The hope is that the DNS database generated will be useful for physics based improvements of RANS and LES models.