Experimental Investigation of Cavitation Phenomena Around the Body with the Conic Nose and Cylindrical Afterbody

In this paper, the inception, growth and development of cavitation are investigated around the combined body experimentally. The diameter of afterbody and the length of model are 25 and 210 mm respectively. The angles of conic nose are 〖30〗^° and 〖45〗^°. Models were tested in a high speed closed circuit cavitation tunnel. A peripheral groove is established on the afterbody and then one conic nose, experiments are repeated in these cases. A comparison was done between all cases. For 〖30〗^° model with groove on afrebody and without groove, cavitation is initiated at a small distance behind the body. If the groove is established on the nose then cavitation is initiated into it. In 〖45〗^° model, cavitation is initiated on the interface of the nose and afterbody. Into the groove and behind of afterbody, cavitation will be initiated at the center of vortex resulted by separation. By developing the length of cavitation on the afterbody, regular longitudinal oscillations will be occurred. Behind the model, inside the wake of body, cavitation initiates at the center of annular vortex. After developing the length of cavitation area ,bubble shedding occurs at the end of cavitation region. During the fluctuating of cavitation area, bubble shedding occurs randomly. In these cases, intense noise is heard.