On the applicability of background oriented optical tomography for large scale aerodynamic investigations

Abstract

 Density fields of the blade tip vortices from a helicopter in hover flight were visualized by a technique which does not require any installation on the helicopter or close to it. The results illustrate an encouraging prospect for the applicability of the technique. It offers the capability of at least qualitative investigations of unsteady density fields even in full-scale flight tests. The underlying principle is briefly described in this article and an extension to a three-dimensional quantitative technique by using multiple cameras is outlined.