Large-Eddy Simulation of Compressible Flow in Asymmetric and Symmetric Planar Nozzles

Large-eddy simulations of supersonic, turbulent flow in asymmetric and symmetric planar nozzles are carried out using high-order finite difference schemes and a large-eddy simulation approach based on explicit filtering. The inflow to the nozzles is from supersonic, fully developed turbulent channel flows at Re-tau=180 and 360 with centerline Mach number 1.2. The combined effects of expansion and acceleration of the flow in this geometry result in reductions of mean pressure, density, and temperature as well as a reduction of Reynolds stresses. The asymmetry of the nozzle leads to notable differences in the aforementioned effects near the straight and the curved walls. It is shown that the decay in Reynolds stresses is more near the curved wall than near the straight wall of asymmetric nozzle, and it is nearly the same near both walls of the symmetric nozzle. Effects of longitudinal streamline curvature are found to be localized near the curved wall of the asymmetric nozzle and are quantified. The aforementioned effects of acceleration, expansion, and streamline curvature are found to be similar in the flow cases with two different Reynolds numbers, although with increasing Reynolds number, subtle differences in these effects are found.