Flowfield measurements in the wake of a missile at high angle of attack

Abstract

The flowfield about a vertically-launched surface-to-air missile model at an angle of attack of 50 degrees and a Reynolds number of 1.1x10(5) was investigated in a low-speed wind tunnel at the Naval Postgraduate School. Determined were the location and intensity of the asymmetric vortices in the wake of the model using planar velocity vector, total pressure coefficient, and vorticity plots. Two model configurations were tested: one at a roll angle of 0 degrees (the "+" configuration) and the other at a roll angle of 45 degrees (the "x" configuration). Two flowfield conditions were used: one with no turbulence and the other with turbulence of a length scale on the order of the size of the nose-generated vortices. The following conclusions were reached: 1) the addition of turbulence changed the magnitudes of the variables without changing the patterns in the plots; 2) changing roll angle significantly altered the patterns of the plots; 3) in general, the locations of the vortices as indicated by the velocity plots do not coincide with the centers for the pressure or vorticity plots; 4) total pressure losses coincide with changes in magnitude of side force as noted in an earlier study.