DNS of a Large-Domain, Mach 3 Turbulent Boundary Layer: Turbulence Structure

Abstract

We introduce a Mach 2.9, Re? = 640, spatially developing direct numerical simulation on a very large domain which is about 60 incoming boundary layer thicknesses long in the streamwise direction. Using the rescaling technique of Xu & Martin, 1 with the rescaling plane taken near the exit, at about 57 incoming boundary layer thicknesses (just under 0.4 meters downstream of the inlet), we obtain a clean inflow with a good sampling of even the largest scales. We show that the simulation can be run for long times ‚ 450‐/U1 without the forcing of artificial acoustic modes in the free stream. We proceed to examine the turbulence structure through spectral analysis and filtered instantaneous flow fields. Special attention is paid to the largest structures, with turbulence modeling, especially aspects unique to compressible boundary layers, in mind.