An improved k−ω turbulence model applied to recirculating flows

In this paper an improved k−ω turbulence model is proposed, which brings the asymptotic boundary value for ω into accord with direct numerical simulation (DNS) data. In the new ω-equation both a turbulent and a viscous cross-diffusion term are included, justified by an analogy to the Yap-correction and the pressure-diffusion process, respectively. The importance of cross-diffusion terms in removing the freestream sensitivity with respect to ω for free shear flows is shown. The performance of the model is evaluated and compared with DNS and with other turbulence models in a channel flow, a backward-facing step flow and a rib-roughened channel flow with heat transfer. The model requires neither wall-function nor wall-distance information and is fully integrable over the near-wall region.