噴流クラウドキャビテーションの壊食特性に与える噴流用ノズル拡大部の影響

（特に，画像解析などに基づいて）

抄録

In this study, we performed erosion test and observation of colliding jets, including the presence or absence of divergent part and axisymmetric convergent - divergent nozzles with different divergent shapes, in order to clarify the effects of the nozzle divergent part on erosion. When the nozzle has divergent part, the cavitation state changes to a typical periodic state of cloud cavitation. It causes a large amount of erosion, compared with the nozzle without divergent part. As a result of the experiments using nozzles with different divergent angles, the erosion characteristics change depending on the shape of the divergent part. We compared experimentally the appearance of cloud cavitation with the erosion characteristics through the cloud observation and the image analysis.