Investigation of Supersonic Wakes Using Conventional and Hybrid Turbulence Models

Abstract

Transitional and turbulent supersonic wakes behind axisymmetric bodies with a blunt base are investigated numerically using state-of-the-art Reynolds averaged Navier-Stokes models and the flow simulation methodology. The centerpiece of the flow simulation methodology is a strategy to provide the proper amount of modeling of the subgrid scales. This is accomplished by a contribution function which locally and instantaneously compares the smallest relevant scales to the local grid size. The turbulence closures chosen are a state-of-the-art wall-distance free explicit algebraic stress model, or a standard K-e model for comparison. Axisymmetric Reynolds averaged Navier-Stokes and fully three-dimensional flow simulation methodology calculations are performed on various computational grids for wakes at M = 2.46 for several Reynolds numbers. The data obtained from all simulation strategies are compared with available direct numerical simulation results for the transitional cases and to experimental results at the highest Reynolds number investigated. Of particular interest is the performance of commonly used compressibility corrections and modifications to closure-coefficients specifically derived for high-Reynolds number flows. The ability of the flow simulation methodology to reproduce flow structures found in direct numerical simulations is scrutinized and a reason for the failure of Reynolds averaged Navier-Stokes calculations to correctly predict the base pressure-distribution is given.