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Analysis of Flow Around an Aerial Tactical Pod carried by the A29B Aircraft for Viscous Drag Optimization

Abstract:

The goal of this study is to identify the best geometry for a tactical pod to reduce viscous drag. To accomplish this, the body's geometry has been mathematically described and controlled by a set of shape parameters. The baseline geometry can then be changed to produce different iterations of the pod. Then, a simple method is used to qualitatively predict the drag due to viscosity based on the momentum deficit of the boundary layer at the body's trailing edge. This technique has been improved by incorporating dynamic boundary layer transition calculation when evaluating different geometries. The viscous drag prediction method and a (1+1)-Evolution Strategy optimization algorithm are used to iteratively alter the geometry by perturbing the shape parameters until a shape with the least drag is achieved. At the final stage, the results from the optimization process are compared to the solution of the Transition-SST viscous model for both the baseline and optimized geometries, from which it is confirmed that the viscous drag calculation method based on the momentum deficit of the boundary layer can be effectively used to optimize an axisymmetric body and that including the dynamic calculation of the boundary layer transition is a valid improvement to the method that could lead to better results during the optimization process.