Two noncircular cross-section bodies and a high wing-body configuration at incidence in a low subsonic free stream

Abstract

This experimental study examines the flow characteristics over a square cross-section body with sharp edges, a rectangular one with rounded edges, and a high wing-body configuration, in a low subsonic free stream. Pressure, velocity, force measurements and flow visualization provide a picture of the flow behaviour, locally and globally. Flow visualization and velocity measurements clearly depict the presence of two axial counter-rotating vortices in the leeside of the first two bodies, being mainly responsible for the asymmetric loading at nonzero roll angles, maximizing the side-force at a roll angle of about 25°. For all body orientations there is always a recirculation region at the nose-afterbody junction leeside area, the extent of which depends mainly on the roll angle. Pressure gradients take high values at the corners of the after body cross-section, even when these are rounded. No asymmetries were practically detected for a zero roll angle and pitch angles up to 20° for the examined three models. The wing-body configuration exhibits a higher lift slope and a more negative zero lift angle, compared to the wing-alone case, and the side-force increases monotonically with the roll angle, without showing any maximum in contrast to the other two models.