Blade-Tip Vortex Characterization of a Rotor under Static and Cyclic Pitch Conditions Using BOS and PIV

To characterize the vortex system of a rotor with collective and cyclic pitch settings, an experimental investigation was carried out at the rotor test facility (RTG) of the German Aerospace Center (DLR) in Gottingen. In addition to former studies based on velocity fields from particle image velocimetry (PIV) in the current measurement also a background-oriented Schlieren (BOS) setup was used for the measurement of density gradients caused by the blade tip vortices. This gives the opportunity to combine velocity and density information to yield a highly detailed understanding of the vortex topology and development