Blending of SAS and correlation-based transition models for flow simulation at supercritical Reynolds numbers

In the present study, blending of the SAS model and a correlation-based transition model has been conducted to simultaneously capture the laminar–turbulence transition inside the boundary layer and the unsteady fluctuating flow structure in the wake region. For this purpose, a new blending function was proposed such that the two base models are combined into a single model that enables to predict the characteristics of the flow at the two distinct regimes well, and at the same time to guarantee smooth transition between the two models. The blended model was implemented in a three-dimensional incompressible flow solver based on unstructured meshes. For validation, the flow around a circular cylinder at a supercritical Reynolds number was calculated. The unsteady and time-averaged results by the blended model were compared with those of the base models and the experiments. It was found that the present blended model predicts the boundary layer transition and the unsteady vortex shedding in the wake region well, comparably to the base models. It is concluded the present blended model can be effectively used for predicting flows simultaneously exhibiting laminar–turbulence transition and unsteady fluctuating wake structure in supercritical flow regimes.