Improvement of aerodynamic performance prediction of hawt rotor blades by a crossflow turbulence transition model

Abstract

In the present study, an improved laminar-turbulence transition model γ−Rẽθt−CF+ has been developed for simulating three-dimensional flow transition, including the effect of interaction between the Tollmien-Schlichting and crossflow instabilities. To accommodate the acceleration of the transition process due to the interaction between the two instabilities, a new trigger function was additionally introduced to include the effect of the crossflow instability. Since the main modification was made only in the trigger function, the present model primarily works on local flow variables, and thus can be effectively implemented in the CFD flow solvers based on unstructured meshes by inheriting the advantages of the baseline γ−Rẽθt transition model. For the validations, the present γ−Rẽθt−CF+ transition model was applied to the NREL Phase VI wind turbine rotor blade. It was found that the present model is well established, and is useful for predicting the flows involving three-dimensional laminar-turbulence transition more accurately than the γ−Rẽθt model for simulating horizontal axis wind turbine rotor blade problems.