Wind Tunnel Testing for Drag Reduction of an Aircraft Laser Turret

This study investigated the use of aft-mounted fairings and splitter plates to reduce the drag of a half-scale aircraft laser turret. Forces, moments, and pressure distributions were measured in the AFIT 1.5-m (5-ft) wind tunnel at Reynolds numbers between 3x105 and 9x105 based on the turret diameter. Oil traces indicated the nature of the flow near the surface of the unmodified turret and the surrounding area. Tufts placed on the turret, fairings, and splitter plates showed changes in separation regions when configurations were changed. The flow around the turret was characterized by dominant vortices shedding from the top of the turret and a large trailing wake of vorticity. Splitter plates were ineffective in reducing drag as a result of the strong flow over the top of the turret. A small fairing reduced baseline drag by 49% but was unable to produce attached flow near the turret.