The Effects of Blunt Leading Edges on Delta Wings at Mach 5.8

Abstract

Pressure distributions were measured on a series of four delta wings with subsonic and supersonic leading edges, both sharp and blunt. The blunt leading edge radius was about 0.5 per cent of root chord. Schlieren studies were also made to determine top and side view shock locations. The tests were conducted at a nominal Mach number of 5.8, and at Reynolds numbers between 0.335 x 10^6 and 0.901 x 10^6 based on root chord. Angular settings covered a range -0.2 ≤ w/V ≤ 0.5 in pitch at zero yaw {about -11.5° ≤ a ≤ + 30°), and a range of v/V = ± 0.125 (about ± 7.2°) at a fixed angle of pitch of 11.5°. The effects of bluntness were found to be small. Also, the pressures produced by shock wave interactions with the boundary layer, and the inviscid pressures generated by the blunt leading edges, were found to be small compared with the inviscid pressures producing lift on the basic wing. Spanwise pressure distributions show no similarity to those obtained by linearized theory. Centerline lower surface pressure in pitch at zero yaw is bracketed between the Newtonian value ΔP/q = 2(w/V)^2 and the two-dimensional exact value.