Experimental investigation of a rotor blade tip vortex pair

Abstract This paper presents the results of an experimental study two closely spaced vortices generated by a rotating blade with modified tip geometry. The experiments are carried out in water channel facilities and involve generic one-bladed rotor operating regime near hover. It is equipped parametric fin placed perpendicular to pressure surface tip, which generates co-rotating vortex pair having helical Based on previous obtained fixed wing, series small-scale first out, validate method generation also for blade, obtain qualitative overview its evolution going downstream. A more detailed quantitative then performed larger facility at three times initial scale. By varying parameters, it was possible configuration have almost same circulation. In both experiments, found merge into single wake within one rotation. Particle image velocimetry measurements show that resulting has significantly core radius than from without fin. finding may relevance context blade–vortex interactions, where noise fatigue fluid–structure interactions depend strongly size.