Large-Scale Source Term Modeling of Vortex Generation

Abstract

Methods of modeling vortex generation in computational fluid dynamics without meshing the vortex generating device have been investigated. This is done by adding source terms to the governing equations to create vortices. Previous work in this area has focused on boundary layer control. This study looks at larger scale applications, such as using vortices for force enhancement. Two different approaches are tested. One is to model vortex generators directly, for which an existing method that replaces the force exerted on the fluid by a vortex generator with a source term is used. Also of this type, a simple immersed boundary method is used for comparison. The other approach uses source terms to create specified vortex velocity profiles. A method to add a continuous three-dimensional velocity is formulated and implemented in three ways; explicit calculation of the required forces from the Navier-Stokes equations, direct forcing (setting the velocity as boundary conditions), and penalty-type feedback forcing. After basic testing, all methods are applied in a practical engineering case using a commercial solver.