Impact of Prandtl numbers on turbulence modeling

Abstract

Abstract A low-Reynolds number (LRN) k - ε ˜ turbulence model is devised that includes the near-wall turbulence modeling and turbulent Prandtl numbers σ( k,ε,t ). A secondary source term added in the ε ˜ -equation accounts substantially for the anisotropic production in near-wall regions. Hence, improved predictions of adverse pressure-gradient flows, involving separation and reattachment are obtained with a considerable reduction in the turbulent kinetic energy and length scale magnitudes. The eddy-viscosity formulation responds to both rotational and irrotational strains to better predict nonequilibrium flows. The current model employs no wall function/distance parameter to bridge the near-wall integration as required by conventional k-ε models. Model predictions are compared with direct numerical simulation (DNS) and experimental data; a good correlation is achieved.