Local Correlation-Based Transition Model for High-Speed Flows

Abstract

A local correlation-based transition model is developed for high-speed transitional flows. Through an analysis of self-similar solutions for compressible boundary layers, a new correlation for the maximum ratio between the vorticity Reynolds number and the momentum thickness Reynolds number is established. New empirical high-speed transition correlations are then developed that take account of streamwise instability, nose bluntness effects, and crossflow-induced transition. On this basis, an intermittency factor transport equation is constructed using strictly local variables and is coupled with the shear-stress transport turbulence model. The new model is validated through several basic test cases under a wide range of flow conditions, including high-speed flat plates, sharp/blunt cones, HIFiRE-5, and a circular cone at a small angle of attack. The results show that the proposed model is capable of predicting the transition behaviors induced by streamwise and crossflow instabilities, as well as the aeroheating environment on high-speed geometries with reasonable precision. Future work will focus on extending the model to pressure-gradient and wall-temperature effects and to roughness-induced transition, as well as to applications to complex high-speed vehicles.