RAS one equation turbulence model with non singular eddy viscosity coefficient
ABSTRACT A simplified consistency formulation for Pk/e (production to dissipation ratio) is devised to obtain a non singular Cm (coefficient of eddy viscosity) in the explicit algebraic Reynolds stress model of Gatski and Speziale. The coefficient Cm depends non linearly on both rotational/irrotational strains and is used in the framework of an improved RAS (Rahman Agarwal Siikonen) one equation turbulence model to calculate a few well documented turbulent flows, yielding predictions in good agreement with the direct numerical simulation and experimental data. The strain dependent Cm assists the RAS model in constructing the coefficients and functions such as to benefit complex flows with non equilibrium turbulence. Comparisons with the Spalart Allmaras one equation model and the shear stress transport k o model demonstrate that Cm improves the response of RAS model to non equilibrium effects.