A COMPARATIVE COMPUTATIONAL EXPERIMENTAL INVESTIGATION OF MACH-2 FLOWOVER A REARWARD-FACING STEP

A numerical study of the Mach 2 flow over a rearward-facing step was p erformed using the SPARK Navier-Stokes code as a companion to a compre hensive experimental investigation conducted at the University of Virg inia using Laser-Induced Iodine Fluorescence (LIIF) and Laser Doppler Anemometry (LDA) techniques. Turbulence was modeled with the Baldwin-L omax turbulence model. First, calculations of the Mach 2 nozzle were p erformed and excellent agreement was obtained between the calculated a nd measured velocity profiles one step height upstream of the step. Se condly, comparisons were made between the calculations and measurement s obtained with both planar and pointwise fluorescence techniques for the rearward-facing step Row field. This study represents the first co mparison between in-stream static temperature measurements and CFD cal culations for supersonic Row over a rearward-facing step. Agreement be tween the planar measurements and the calculations was observed regard ing the position of the prominent flow features: the expansion fan, th e shear layer, and the reattachment shock. Significantly lower tempera ture measurements were observed in low-momentum regions of the flow fi eld. Comparisons between the pointwise measurements and the calculatio ns exhibited very good quantitative agreement. The calculated and meas ured pressures, temperatures and velocities agreed within 5% at approx . 85% of the experimental locations.