Experimental investigation on the streamwise vortex-surface interaction

Interaction of a vortex with a blade, wing or fin may involve both rapid distortion of the incident vorticity field and unsteady flow near the surface. A variety of flow visualization methods were applied in the experiment to observe the change of flow characteristics during a streamwise vortex-surface interaction. Particle image velocimetry measurements were carried out on a 2-D flow field in the near-wall area. The topology structure of the flow field during the vortex-surface interaction was obtained. The near-wall vorticity layer caused by the primary vortex formed secondary vortex. The initial strength of the incident vortex and distance between vortex core and the surface are the main parameters that affect the characteristics of flow field. The relevant results will help further study on the mechanism of interaction.