Evaluation of Wall-modeled LES for Turbulent Separated Flows

Speaker: Prahladh Iyer, National Institute of Aerospace
August 27, 2020

Presentation

Abstract

Scale-resolving methods are becoming increasingly popular for the prediction of turbulent separated flows, and recent studies are promising when compared to the more widely used Reynolds-Averaged Navier-Stokes (RANS) methodology. Nevertheless, further understanding of such methods and its associated errors are required before being routinely used in industry for design purposes. In this study, we evaluate the performance of the stress-based wall-modeled large eddy simulation (WMLES) methodology for a number of turbulent separated flow test cases using an unstructured finite volume solver. Detailed comparisons with available experimental and/or higher-fidelity DNS/LES data are used to assess the performance. The equilibrium wall model of Kawai & Larsson [Phys. of Fluids, Vol. 24, No. 1, 2012], and the nonequilibrium wall model of Park & Moin [Phys. of Fluids, Vol. 26, No. 1, 2014] are used in this study. While the primary focus is on the simpler two-dimensional and axisymmetric flows, we briefly discuss some results for more complex three-dimensional flows. Sensitivity of the results to the different wall models, grid resolution and exchange location are reported, and finally, we suggest some general guidelines and challenges for application of WMLES to complex flows based on our observations.

Biography

Prahladh Iyer currently works as a Research Scientist at the National Institute of Aerospace in Hampton, Virginia, and as a resident researcher in the Computational Aerosciences Branch at NASA Langley Research Center. He obtained his Ph.D. in Aerospace Engineering with a minor in Mathematics from the University of Minnesota in 2015. His research interests are broadly in the area of Computational Fluid Dynamics (CFD), with a focus on DNS/LES of turbulent flows, turbulence modeling, laminar-turbulent transition, high-speed flows and numerical methods for complex geometries.

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