Measurements of the paths of the vortex cores shed from the wings of a typical guided-missile model at M = 1.57

Abstract

The paths of the cores of the vortex sheets shed from the wings of a typical guided-missile model, having cruciform rectangular wings mounted on a long cone-cylinder body, have been traced in their movement downstream over a range of incidence and yaw from 5 to 20 deg and 0 to 20 deg respectively at M = 1.57. The measuremenfs have shown that: (a) the cores of the vortex sheets remain very close to the plane parallel to the free stream containing the line of the mid-chords of the wings from which the vortex sheets are shed (b) the movement of the fully rolled-up cores in this plane can, for practical purposes, be attributed entirely to the flow induced by the other wing (c) estimates of the paths of the vortex cores based on slender-body theory do not agree at all well in the regions investigated owing to the presence of strong shock waves and rapid expansions. Estimates of the paths of the vortex cores based on a semi-empirical analysis have shown reasonable agreement, however, and it is considered that approximations similar to those made in these estimates for this configuration would give reliable values for other configurations in the regions near the wings; wall downstream of this region a slender-body theory analysis would probably be satisfactory (d) slender-body theory gives a reasonable estimate of the spacing of the cores of the fully rolled-up sheets at the zero yaw condition. Estimates of the characteristics of four rear surfaces using this vortex spacing have shown satisfactory agreement with experiment (e) further tests to check these conclusions on a large range of missiles seem desirable.