Investigation of supersonic wakes using conventional and hybrid turbulence models

Sandberg, Richard D. and Fasel, Hermann F. (2006) Investigation of supersonic wakes using conventional and hybrid turbulence models. AIAA Journal, 44 (9), 2071-2083. (doi:10.2514/1.20379).

Abstract

Transitional and turbulent supersonic wakes behind axisymmetric bodies with a blunt base are investigated numerically using state-of-the-art RANS models and the Flow Simulation Methodology (FSM). The centerpiece of the FSM is a strategy to provide the proper amount of modelling 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 underlying compressible Navier-Stokes code in cylindrical coordinates developed for this research employs high-order accurate finite differences and a high-order accurate axis treatment.The turbulence closures chosen are a state-of-the-art wall-distance free explicit Algebraic Stress Model (EASMalpha), or a standard K-epsilon model (STKE) for comparison. Axisymmetric RANS and fully three-dimensional FSM 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 to available DNS 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 FSM to reproduce flow structures found in DNS is scrutinized and a reason for the failure of RANS calculations to correctly predict the base pressure distribution is given.

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Contributors

Author: Richard D. Sandberg

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