AERODYNAMIC DRAG ON SPIKED BLUNT BODIES IN LOW-DENSITY HYPERSONIC FLOW

Abstract

Abstract : Aerodynamic drag on spiked blunt bodies was measured in hypersonic, low-density flow of nitrogen. Two models were tested: a spherically capped cone of 10-deg halfangle at 0 < alpha < 40 deg, and a right circular cylinder at alpha = 0. Reynolds numbers, based on total body lengths and free-stream conditions, varied from 200 to 1200. Mach number was constant at 10.1. Results were compared with modified Newtonian and free-molecule calculations. Effects of hypersonic rarefied flow are apparent, with drag coefficient increasing for large angles of attack for all spike lengths. A correlation procedure suggested in an earlier report for a large class of similar bodies at 0-deg angle of attack is shown to be effective in the case of spiked bodies too. It is apparent that the marked reduction of drag effected by use of spikes on blunt- nosed bodies at higher Reynolds numbers is greatly diminished when low Reynolds numbers exist. However, a moderate reduction is shown for small angles of attack at the Reynolds numbers of the present experiment.