Vortex Asymmetry and Induced Side Forces on Elliptic Cones at High Incidence

TLDR: In this article, the authors investigated features of vortex asymmetry and induced side forces on a family of three elliptic cones at subsonic speeds, and found that ellipticity progressively reduces the angle of attack for the onset of side force up to an ellipticity ratio (defined here as the ratio of major to minor axis) of 143.

Abstract: Experimental studies were carried out investigating features of vortex asymmetry and induced side forces on a family of three elliptic cones at subsonic speeds Measurements of forces, moments, and surface flow visualization studies were made up to an angle of attack of 45 deg over a wide range of Reynolds number Results show that ellipticity progressively reduces the angle of attack for the onset of side force up to an ellipticity ratio (defined here as the ratio of major to minor axis) of 143, beyond which there is a reversal in this trend for both horizontal as well as vertical orientations of the ellipse Interestingly, the (maximum) side force magnitudes are larger for the horizontal compared to the vertical ellipse orientation on each model A correlation of the angle of attack for the onset of asymmetry on pointed forebodies with elliptic cross section is suggested These results provide strong support to the hypothesis (often made in the literature) that inviscid mechanisms may play a key role in triggering asymmetry of vortex flows