3D Volumetric PIV Measurements on a Hovering Model Rotor

A first application of volumetric Particle Image Velocimetry (3D-PIV) was performed in 2005 with a HOver TIp vortex Structure test (HOTIS) in the rotor preparation hall of DLR Braun-schweig using a 40% Mach scaled model rotor of the Bo105. Major emphasis was placed on three component (3C) measurements in planes following each other as close as the resolution within each plane to form a 3D volume of the blade tip vortices. They were traced from their creation 1deg behind the trailing edge up to half a revolution. This paper deals with preliminary results obtained for vortex aging, RPM and thrust variation, and special effects observed in 3D volumetric data of young rotor blade tip vortices (age 3deg). In addition to PIV the background oriented schlieren technique (BOS) was applied to measure optically the density within the core radius at young vortex age