In supersonic and hypersonic flows, the near-wall density variation due to wall cooling poses a challenge for accurately predicting the near-wall velocity and temperature profiles using classical eddy viscosity turbulence models. Compressible turbulent boundary layers are known to follow the universal wall law via semilocal transformation. However, developing a turbulence model that predicts a velocity profile, which, via semilocal transformation, follows the universal wall law, remains challenging. The current paper builds upon Danis–Durbin’s practice of modifying the Formula: see text equation and proposes a simple modification to the Formula: see text two-equation model. The formulation of the proposed modification involves dimensional analysis and the proper selection of the local length scale. The newly introduced modification is used to modify the slope of the velocity profile starting from the viscous layer to above. It recovers a semilocal scaling of turbulent kinetic energy, viscosity, and eddy frequency, then achieves a very decent correction of the velocity profile in compressible turbulent channel flows, satisfying the universal wall law after applying Trettel and Larsson’s transformation. The proposed new Formula: see text model can also improve the velocity and temperature predictions in strongly wall-cooled zero-pressure-gradient hypersonic turbulent boundary layers, compared to the original Formula: see text model. Validation using the favorable and adverse pressure gradient boundary layers suggests that the model does not impose a negative effect on the original Formula: see text model.
Zifei Yin (Mon,) studied this question.