Investigation of flow structures in a turbulent separating flow using hybrid RANS-LES model

Abstract

Purpose

Hybrid Reynolds-averaged Navier–Stokes large eddy simulation (RANS-LES) methods have become popular for simulation of massively separated flows at high Reynolds numbers due to their reduced computational cost and good accuracy. The current study aims to examine the performance of LES and hybrid RANS-LES model for a given grid resolution.

Design/methodology/approach

For better assessment and contrast of model performance, both mean and instantaneous flow fields have been investigated. For studying instantaneous flow, proper orthogonal decomposition has been used.

Findings

Current analysis shows that hybrid RANS-LES is capable of achieving similar accuracy in prediction of both mean and instantaneous flow fields at a very coarse grid as compared to LES.

Originality/value

Focusing mostly on the practical applications of computation, most of the attention has been given to the prediction of one-point flow statistics and little consideration has been put to two-point statistics. Here, two-point statistics has been considered using POD to investigate unsteady turbulent flow.

Citation

Kumar, G., De, A. and Gopalan, H. (2017), "Investigation of flow structures in a turbulent separating flow using hybrid RANS-LES model", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 27 No. 7, pp. 1430-1450. https://doi.org/10.1108/HFF-03-2016-0134