Modeling of Heat Flux Overshoot in the High-Speed Boundary-Layer Transition

Accurately predicting the heat flux overshoot induced by boundary-layer transition is a critical topic in the thermal protection system design of hypersonic vehicles. In this paper, a transition-turbulence prediction model based on the Reynolds-averaged equations with local-variable dependence is established. By constructing an adaptive modulation function that activates only in the transition region and acts on the source term of the intermittency factor equation, the intermittency factor and turbulent kinetic energy in the transition region are appropriately increased locally, thereby achieving an accurate simulation of the heat flux overshoot phenomenon. It should be noted that this modification does not affect the prediction accuracy for cases without heat flux overshoot. Moreover, through reasonable modeling, the influence of the overshoot correction on the predicted transition location is prevented. Validations using direct numerical simulation and wind-tunnel test data from several supersonic and hypersonic boundary-layer transition cases demonstrate that, as compared with the original unmodified prediction model, the improved transition prediction model proposed in this paper significantly enhances the prediction accuracy of heat flux overshoot in the transition region.