Evaluation of the Tip Vortex Flowfield at the Rotor Test Facility Göttingen

Abstract

This thesis describes and evaluates experiments conducted on a rotor test facility with a focus on blade tip vortices. The flow field of a four-bladed rotor was studied with the particle image velocimetry (PIV) method to visualise the flow field. The experimental setup and procedure is described in detail as well as the computer based evaluation techniques. Interesting vortex interaction is discovered and interaction and vortex parametres are studied when varying parametres such as blade angle of incidence and axial inflow speed. A basic understanding of blade tip interaction for the test facility is gained and experimental data for future investigations is gathered. Vortex interaction is found to occur when axial inflow is sufficiently slow, suggesting the interaction to be caused as an effect of vortex separation. Studies of vortex merging and effects of Phase averaging PIV images are also discussed.