A theoretical model evaluating leading order vortex decay behind an aircraft

Abstract

A theoretical model in this article which is used to evaluate leading order vortex decay behind an aircraft, is presented. This model is then applied to two important problems. The first evaluates safety separation distances for the super class of aircraft exemplified by the Airbus A380. The second evaluates the swirl parameter which is shown to decay to a sufficiently low level that short-wave instabilities are likely to be instigated. The model uses the Oseen approximation, which assumes that in the far-field the ratio of the perturbed velocity to the aircraft velocity is small, and developed from recent publications by the first author. The atmospheric turbulence is incorporated into the model by using effective viscosity.