Wall-distance free wray-agarwal turbulence model with elliptic blending

This paper describes several extensions to the original Wray-Agarwal model (WA2017) to improve its implementation and accuracy. The extensions include (1) modification to the model to remain accurate and robust under the special condition of zero-strain rate in the flow field, (2) a wall distance free (WDF) formulation to provide improved accuracy near curved surfaces, and (3) elliptic blending to improve the accuracy of wall bounded mildly separated flows. The accuracy of the improved model (WA2018-EB) is tested by computing a number of benchmark test cases from NASA Turbulence Modeling Resource (TMR) website. Computational results for fully developed turbulent channel flow at different Reynolds numbers, flow over NASA wall-mounted hump, flow in an asymmetric planar diffuser, flow past a backward facing step, flow past a curved backward facing step, flow over a periodic hill, flow past an axisymmetric transonic bump, and flow past an axisymmetric corner with shock/boundary layer interaction are presented. It is shown that the improved WA model (WA2018) with elliptic blending (WA2018-EB) has better agreement with the experimental data for majority of test cases.