Performance of unstructured hybrid Reynolds averaged Navier-Stokes/large-eddy simulation methods in simulating shear-driven cavity flows

Abstract

Two separate, unstructured hybrid RANS/LES methods are used to simulate both resonant and nonresonant shear-driven cavity flows. The first method uses an upwind-biased discretization for the inviscid flux calculations in the governing equations, along with a nonlinear k−e turbulence closure for RANS regions, and the Smagorinsky subgrid-scale closure for LES regions. The second method uses an upwind-biased discretization for the inviscid flux terms which is modified to reduce the inherently high dissipation in the associated Riemann solver when applied to cell faces not orthogonal to the flow direction. The second method uses a k−e closure for RANS regions. In LES regions, the second method solves a transport equation for subgrid turbulent kinetic energy, relating this energy to a spectrum for the energy-inertial-dissipation range, which allows calculation of a less dissipative eddy viscosity. Both methods are applied to a three-dimensional, deep cavity problem, at resonant and nonresonant flow conditions. Resulting pressure-time series are compared to experimental measurements.