Stability-Based Transition Transport Modeling for Unstructured Computational Fluid Dynamics Including Convection Effects

Abstract

A transition transport model for unstructured computational fluid dynamics is presented, which is based on a stability-based semi-empirical criterion including convection effects. To be compatible with computational fluid dynamics solvers, the underlying transition criterion is computed using three additional transport-type partial differential equations. A fourth equation is used in order to define laminar and turbulent regions inside the flowfield. The model was implemented in the finite-volume solver TAU of the German Aerospace Center (DLR). It could be shown that a widely used transition transport model seems to exceed its range of validity for particular cases at high and low Reynolds numbers (for low turbulence intensities) depending on the pressure distribution. For the proposed model it is shown that for these cases transition onset can be predicted with the desired accuracy. To demonstrate this, computations of several 2D airfoils were performed, which show very good agreement with experimental data. Additionally, the applicability for industrially relevant weakly compressible (Ma<0.3) 3D configurations and a compressible 3D wing–body configuration was shown achieving good agreement with experiments.