Towards density reconstruction of helicopter blade tip vortices from high-speed background-oriented schlieren data

Abstract

A method for the reconstruction of 3D density distributions of blade tip vortices is presented. The reconstruction is performed using a filtered back-projection on 2D density gradient data from a high-speed LS-BOS (laser-speckle-illuminated background-oriented Schlieren) setup, captured during the STAR (smart-twisting active rotor) project. Density profiles of blade tip vortices are presented, as well as comparisons of the size and development of the vortices. In addition the comparison to a PIV (particle image velocimetry) measurement is shown.