Errors Characterization of a RANS Simulation

Abstract

This research uses data from direct numerical simulation (DNS) to characterize the different errors associated with a Reynolds-averaged Navier–Stokes (RANS) simulation. The statistics from DNS (Reynolds stresses, kinetic energy of turbulence, κ, and dissipation of turbulence, ε), are fed into a RANS simulation with the same Reynolds number, geometry, and numerical code used for DNS. Three integral metrics error based on the mean velocity, the moduli of the mean rate-of-strain tensor, and the wall shear stress are used to characterize the errors associated with the RANS technique, with the RANS model, and with the linear eddy viscosity model (LEVM). For developed and perturbed flow, it is found that the mean velocity of the RANS simulations with the DNS statistics is almost the same as the mean velocity from DNS data. This procedure enables the study of the relative importance of the different Reynolds stresses in a particular flow. It is shown that for the bounded perturbed turbulent flows studied here, almost all the necessary effects of turbulence are contained in the Reynolds shear stress.