Aerodynamic characteristics of configurations having bodies with square, rectangular, and circular cross sections

Abstract

Wind-tunnel tests, at a Mach number of 0.75, for three families of configurations are described. Three bodies, having identical cross-sectional area and length, were tested alone and with three sets of fins. Their cross sections are a square with rounded corners, a rectangle with rounded corners, and a circle. For configurations having identical fins, the normal-force curve slope was found to be larger for the family with the square body than for that with the circular body and to be largest for configurations with the rectangular body. A component buildup method, which uses experimental data for body alone, lifting-surface analysis for wing alone, and slender-body theory for the influence coefficients, has been developed. The predicted normal-force curve slope is 6-17% larger and the center of pressure is 0.15-0.25 reference lengths more aft than those experimentally determined. Results obtained by the VORLAX, with corrections for body alone code based on test data, are very close to those obtained by the component buildup method. This agreement validates the use of slender-body theory for the evaluation of wing-body mutual influence coefficient for configurations having noncircular bodies.