Computational Fluid Dynamics Testing for Drag Reduction of an Aircraft Laser Turret

A computational study was conducted on the use of aft-mounted fairings for passive drag reduction on a sphere at ReD=8.66x10 5. The sphere dimensions and operating Reynolds number were selected to approximate (in two dimensions) the flow around a proposed aircraft laser turret for which experimental data was available. To establish the validity of the computational model, flow predictions were compared to sphere data available in the open literature. The model, exercised in both the laminar and turbulent modes, showed good agreement with the published data. Two proposed laser turret fairings were then evaluated computationally: a large fairing (beginning at 49.5 degrees past the sphere apex) and a small fairing (beginning at 58.95 degrees past the sphere apex). Existing wind tunnel models were used to generate axisymmetric computational grids that approximated the geometry of these models.