Aerodynamics of Wrap-Around Fins in Supersonic Flow

Abstract

Existing supersonic fin theory has been modified to compute the pressure distribution over a wrap-around fin. Evvard’s theory has been used to calculate the pressure loading due to angle-of-attack on a wrap-around fin by including fin curvature as a variable in the definition of the zones of influence. Evvard’s theory uses the intersections of the fin surface and the Mach cones originating from the leading edge discontinuities to split the fin surface into regions of influence. For a planar fin, the intersections are linear; however, the intersections on a curved fin form curved lines. By redefining the Mach lines to account for fin curvature and using an empirically derived induced angle-of-attack, the application of Evvard’s theory can be extended to accurately compute the unique aerodynamic characteristic of wrap-around fins.