Two-Layer Reynolds-Stress Model for Strong Adverse-Pressure-Gradient Wall Flows

Accurately modeling turbulent boundary layers under strong adverse pressure gradients remains a challenge of importance for industrial applications. This challenge can be effectively addressed by Reynolds stress models (RSMs), but an analysis of the theoretical behavior of standard RSMs revealed limitations. Particular limitations include the incorrect prediction of the logarithmic-layer slope and the absence of a square-root zone when a strong adverse pressure gradient is encountered. To address these issues, a two-layer elliptic blending model with a specific dissipation scale is proposed. This new model successfully predicts key flow features, including the correct slope for both the logarithmic and square-root zones under a strong adverse pressure gradient.