Numerical simulation of a turbulent flow near a right-angled corner using the Speziale non-linear model with RNG K– ε equations

Abstract

A numerical simulation has been performed with the non-linear turbulence model proposed by Speziale (1987)On non-linear k–l and k– ε models of turbulence, Journal of Fluid Mechanics, 178, 459–475, coupled with the K– ε equations coming from the renormalization group theory (RNG) derived by Yakhot et al. (1992) Development of turbulence models for shear flows by a double expansion technique, Physics of Fluids A, 4, 1510–1520. The fully developed turbulent flow through a straight square duct, involving secondary motion, is simulated. The results are compared with the DNS data and measurements. The non-linear model was capable of predicting secondary flows, but underpredicted their intensity. The comparison between model predictions, DNS data and measurements are shown and commented for the streamwise, spanwise velocities and Reynolds stress tensor. The terms of the streamwise vorticity equation are computed and compared with DNS data. The predictions obtained with the RNG K– ε model show small improvements when compared with the standard K– ε.