Some experiments on delta wings in hypersonic flow.

Abstract

An exploratory experimental investigation was made of flat delta wings at angles of attack.The tests were made in the Princeton University Helium Hypersonic Wind Tunnel at Mach number 11.8 and at Reynolds numbers based on leading edge thickness ranging from 4200 to 28,000. The leading edges of the models used in the investigation were swept back at angles of 60° and 70° and had thicknesses of 0.005 in. and 0.030 in. The angle of attack of the models was varied from 0° to 50°. Static pressures and flow directions were measured on the surface of the model. The resulting data were analyzed, and the pressure measurements correlated with the viscous interaction parameter were evaluated using conical flow properties. The effect of leading edge and apex bluntness on static pressures was examined and shown to be present in various degrees throughout the spectrum of angle of attack tested. Blunting the apex and the leading edge are shown to cause unexpected effects on the pressure distribution along the leading edge. The flow in the boundary layer was shown to have strong spanwise tendencies in both the low and high angle-of-attack regimes, and to depend on bluntness. The concepts of spanwise and chordwise strip theory are discussed and applied to the analysis of the experimental data. C r M P RN S T t a A /* 6 X 4L Kd KM x y z (L/Z)) U Nomencl ature root chord Mach number pressure Reynolds number distance from centerline taken normal to the leading edge distance from centerline to the leading edge taken normal to the leading edge temperature thickness of leading edge angle of attack sweep angle coefficient of viscosity local inclination to freestream velocity viscous interaction parameter centerline 8 cota axial dimension lateral dimension in plane of wing lateral dimension normal to plane of wing maximum lift-to-drag ratio freestream velocity out flow angle in plane of the wing body inclination Subscripts LE = leading edge w = wedge 0 = total conditions t = leading edge thickness b = body conditions s = shock c = cone oo = freestream conditions ( ) e -edge of boundary layer N = normal