Characteristics of supercavitating flows around a hydrofoil

Supercavitation around a hydrofoil is studiedexperimentally to address the flowing characteristics. A high-speed videocamera is used to visualize the flow structures under different cavitationnumbers. The digital particle image velocimetry (DPIV) is employed tomeasure the velocity fields. The bubbles among the cavitating fields areused as the tracer particles to survey the velocity distribution inside thecavity and improve the tracking capability of the tracer particles. Theresults show that three distinct supercavitating flow regimes can beobserved with the decreasing cavitation numbers, in which the cavitationstructure varies with the distribution of the water-vapor mixing phase andvapor phase. A large velocity gradient exists around the interface betweenthe cavitation area and the free stream. In the cavitation area, thelower-velocity region moves from the foil's middle part to the downstreamwith the decrease of the cavitation number. The fluid velocity is low in thewater-vapor mixture region, while with the similar distribution in the freestream and the vapor region.