LONGITUDINAL AERODYNAMIC PERFORMANCE OF A SERIES OF POWER-LAW AND MINIMUM-WAVE-DRAG BODIES AT MACH 6 AND SEVERAL REYNOLDS NUMBERS

摘要

Experimental data have been obtained for two series of bodies at Mach 6 and Reynolds numbers, based on model length, from 1.4 x 106 to 9.5 x 106. One series consisted of axisymmetric power-law bodies geometrically constrained for constant length and base diameter with values of the exponent n of 0.25, 0.5, 0.6, 0.667, 0.75, and 1.0. The other series consisted of positively and negatively cambered bodies of polygonal cross section, each having a constant longitudinal area distribution conforming to that required for min¬imizing zero-lift wave drag at hypersonic speeds under the geometric constraints of given length and volume.nAt the highest Reynolds number, the power-law body for minimum drag is blunter (exponent n lower) than predicted by inviscid theory (n = 0.6 instead of n = 0.667);however, the peak value of lift-drag ratio occurs at n = 0.667. Viscous effects were present on the bodies of polygonal cross section but were less pronounced than those on the power-law bodies. The trapezoidal bodies with maximum width at the bottom were found to have the highest maximum lift-drag ratio and the lowest minimum drag.