2009 年 4 巻 p. 77-85
Impact force around a cavitating jet can be utilized for surface modification to improve fatigue strength of metallic materials. A peening method by cavitation impacts is called cavitation shotless peening (CSP), as shots are not required. For making practical use of CSP, enhancement of capability of the cavitating jet is required. In the present paper, an optimum nozzle outlet geometry that the mass loss shows the maximum was found by changing the nozzle outlet geometry through erosion test. In addition, the discharge frequency of cavitation clouds, Strouhal number and cavitation impacts by changing with nozzle outlet geometry were measured. It was revealed that nozzle outlet geometry affected the capability of the cavitating jet, the frequency of impacts, Strouhal number and the maximum value of cavitation impact force.