An anisotropic shear stress transport (ASST) model formulation

Computational fluid dynamics is nowadays a primary tool for a variety of engineering applications. Aeronautic, chemical, nuclear, marine engineering use available models to provide high technological products. Isotropic Reynolds-average Navier–Stokes (RANS) turbulence models are widely used and their strengths and drawbacks are very well known. Nevertheless, since they are not supposed to provide accurate results for the most complex flows, Reynolds stress transport (RST) models are proposed to take into account for strong anisotropies. However its numerical behavior is often too expensive for industrial applications. Alternative models as URANS, LES or DNS are far from an intensive industrial application. Hence, a non-linear eddy viscosity (NLEV) model is proposed, which is shown to give very accurate results for a large variety of flow application with minor computation effort needed, compared to traditional RANS models. In particular it consists of a quadratic stress–strain relation with variable coefficients, which can capture secondary fluid motion, coupled with the SST turbulence model proposed by Menter, which is supposed to correctly represent the shear stress for adverse pressure gradient flows.