Modification of the k-kl Two Equation Turbulence Model for Improved Jet Flow Predictions (Invited)

Abstract

Reynolds averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) methods are relied on for design and analysis of both conventional and STOVL tactical military aircraft. Application of one and two transport equation turbulence models is the standard approach used to account for the effects of turbulence. While the commonly used turbulence models predict flows in wall boundary layers and wakes with reasonable accuracy, they typically do not predict jet flows well. As a result, predictions of jet effects and jet environments as part of vehicle computations are inaccurate when these models are used. In this work, modifications that improve jet flow predictions for the k-kl two transport equation turbulence model are presented. The improved model gives accurate predictions of wall turbulent boundary layers and 2-D shear layers consistent with the baseline k-kl model. Results for the modified model are presented for a series of subsonic, near sonic and hot axisymmetric jet flows. While the baseline k-kl model gives results that are comparable in accuracy to other commonly used turbulence models, the modified model gives much more accurate results for all of the jet flows considered while maintaining accuracy for a wall turbulent boundary layer.