Multi-Scale Turbulence Model in Simulation of Supersonic Crossflow

Abstract

§**†† Hybrid Reynolds-averaged Navier-Stokes/large eddy simulation modeling approaches are convenient for flows where parts of the flowfield can be solved well with Reynolds-averaged Navier Stokes (RANS) models and large eddy simulations (LES) can be used in areas where the flow contains complex turbulent. This work is aimed at assessing the capability of a multi-scale hybrid RANS/LES computational modeling approach in solving an Ethylene injection case into supersonic crossflow. This approach allows for the computation to have a large range of varying grid size, geometry and flow regimes as it smoothly varies the eddy viscosity to resolve turbulent structures consistent with the grid. Fuel concentration and eddy viscosity contours reveal physical turbulent structures that increase with grid refinement. Predictions of the time averaged fuel mole fraction from the hybrid model are improved over RANS simulations when compared to experimental measurements. Turbulent fluctuations are collected to estimated resolved mass diffusion and momentum eddy viscosities. The resolved mass and momentum diffusion show large variations in turbulent Schmidt number.