Experimental study of cavitating flows of protuberance on the surface of underwater vehicle

The high-speed movement of the underwater vehicle causes cavitation in the flow field. For the underwater vehicle with protuberances on the surface, the geometric shape of the protuberance is bound to affect the local flow field of the underwater vehicle. Furthermore, it affects the generation, development and shedding of cavitation around the vehicle. In order to explore the influence of the geometric shape of the protuberance on the generation and development of the cavitation phenomenon, the experimental and high speed imaging technology are carried out to study the cavitation characteristics of the protuberance on the surface of the underwater vehicle. The results show that with the continuous decrease of vertical motion pressure, the cavitation number decreases gradually, the cavitation scale increases continuously and the phenomenon of periodic shedding occurs. Different shapes of protuberances produce different cavitation effects. The increase of protuberance height can restrain the shedding of cavitation bubbles and form larger cavitation bubbles. The shape of the arc-shaped protuberance can inhibit the occurrence of cavitation and produce fewer cavitation bubbles. The size of the cavitation bubbles produced by the bevel-shaped protuberance is larger, but the cavitation bubbles shedding frequency is also higher. •Different protuberance produce different cavitation phenomena. .•The protuberance with a 45° inclined front end is conducive to the development of cavitation bubbles.•The cavitation caused by the protuberance will cause the regular shedding of the hairpin vortex. .