WIT Press

Parallel Vorticity Formulation For Calculating Lift And Drag On Bluff Bodies In A Free Stream


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D. G. Tipton, M. S. Ingber & M. J. Brown


Parallel vorticity formulation for calculating lift and drag on bluff bodies in a free stream D. G. Tipton1, M. S. Ingber1 & M. J. Brown2 1Engineering Sciences Center, Sandia National Laboratories, New Mexico, USA 2Department of mechanical Engineering, University of New Mexico, USA ABSTRACT: A parallel vorticity code is developed to study flows over bluff bodies in a free stream. The vorticity method has certain advantages over primitive variable methods for incompressible flows including a reduced equation set through the elimination of the pressure variable. However, because pressure is eliminated, the calculation of aerodynamic coefficients such as lift and drag must be performed in postprocessing. In the current research, an efficient method for recovering the pressure field locally on a body in a free stream is developed. In order to analyze large wake regions, a parallel implementation of the vorticity code is developed. The vorticity code is based on a three-step algorithm. The first step involves determining vortex sheet strengths on the surface of the body which yields Neumann boundary conditions for the vorticity equation. The second step involves determining the interior velocity field using the generalized Helmholtz decomposition representing the flow kinematics. The third step involves solving the vorticity equation. Each step requires a separate parallel strategy. The parallel efficiency of the overall algorithm is evaluated by considering the benchmark problem of flow over a cylinder.