Effectiveness of side force models for flow simulations downstream of vortex generators

Vortex generators are a widely used means of flow control, and predictions of their influence are vital for efficient designs. However, accurate computational fluid dynamics simulations of their effect on the flowfield by means of a body-fitted mesh are computationally expensive. Therefore, the Bender-Anderson-Yagle and jBAY models, which represent the effect of vortex generators on the flow using source terms in the momentum equations, are popular in industry. In this contribution, the ability of the Bender-Anderson-Yagle and jBAY models to provide accurate flowfield results is examined by looking at boundary-layer properties close behind vortex generators. The results are compared with both body-fitted mesh and other source term model Reynolds-Averaged Navier-Stokes simulations of three-dimensional incompressible flows over flat-plate and airfoil geometries. The influence of mesh resolution and the domain of application on the accuracy of the models is shown, and the influence of the source term on the generated flowfield is investigated. The results demonstrate the grid dependence of the models and indicate the presence of model errors. Furthermore, it is found that the total applied force has a larger influence on both the intensity and shape of the created vortex than the distribution of the source term over the cells.2016 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.