A Blended Model for Simulating Massive Flow Separation and Laminar-Turbulence Transition

Abstract

In the present study, blended models, which combine hybrid RANS/LES models and a correlation-based transition model, have been developed for simulating the flow containing massive flow separation and laminar-turbulence transition inside the boundary layer. To ensure that the base models work well in their own flow regimes of interest, and to achieve smooth transition between the flow regimes, a new blending function was developed based on an empirical analogy from Menter’s k-ω SST turbulence model. The new blended models were implemented in a three-dimensional incompressible flow solver based on unstructured meshes. Validations of the blending function and the blended models were conducted for a circular cylinder at a supercritical Reynolds number, an airfoil at high angle of attack, and a dynamic stall problem of an airfoil. The results of the blended models were compared with those of the base models and the experiments. It was found that the new blended models works well by simultaneously capturing the boundary layer transition and the massive flow separation, compared to the base turbulence models.