Simulation of Various Turrets at Subsonic and Transonic Flight Conditions Using OVERFLOW

摘要

In this work, the flowfields associated with two canonical turret geometries, a fully exposed hemisphere on a flat plate and a 50% submerged hemisphere on a flat plate, were simulated using the OVERFLOW 2 flow solver. Both turret geometries use a flat-window aperture with an aperture ratio (ratio of the aperture diameter to the turret diameter) of 0.295 and an elevation angle of 57 deg. The forward field of regard was the particular focus in this study, and both symmetric (azimuth angle of 0 deg) and asymmetric (azimuth of 45 deg) window orientations were examined. Two flight conditions were also studied: a subsonic case with M = 0.45 and Re_D = 6.30×10~6 and a transonic case with M = 0.85 and ReD = 9.53 ×10~6. The flowfield was simulated using the delayed detached-eddy simulation capability of OVERFLOW in conjunction with the spatially fifth-order weighted essentially nonoscillatory scheme to capture the off-body vortical structures. The impact of the turret aerodynamics on the performance of the turrets for directed energy applications is inferred through consideration of the flow features, density and pressure fluctuations, and forces on the turrets.