Turbulence Model Data Derived from Direct Numerical Simulations

Abstract

With the aid of direct numerical silulation results, modelling of turbulence is examined. Because it is possible to calculate up to third order moments from the database any model assumptions used in turbulence models can be tested by direct comparison of the individual terms. In case of low-Re k-epsilon models various damping functions in the eddy viscosity relation are checked with the results from direct numerical simulation. The deduced near-wall asymptotic behaviour of the various quantities is used to analyze the different modelled terms. Closure models for the diffusion terms in the Reynolds-stress-, kinetic energy and dissipation rate equations are evaluated. Furthermore algebraic models for the dissipation rate of the Reynolds stresses and for the pressure-strain correlation are tested in detail. All testing is done against direct numerical simulation data of turbulent channel flow at low Reynolds number. If possible the various turbulence model constants are calculated directly from the simulation data.