Collapsing behavior of cavitation bubbles is a very short phenomenon. In this study a new ultra-high-speed video camera with the maximum frame speed of 106 fps is used to observe the detailed aspects of three cavitation patterns such as separated vortex cavitation in a convergent-divergent channel, Karman-vortex-like cavitation in the wake flow of a circular cylinder and vibratory cavitation in an ultrasonic vibratory apparatus. For a convergent-divergent channel, the re-entrant motion within the separation zone was observed together with bubble collapse in the divergent part. It was found that minute bubbles collapsed in a chain-reaction manner inside the separated zone with the re-entrant motion after the shedding of cavitation cloud. For the wake flow of a circular cylinder, a collapsing motion of cavitation was observed as an axial-collapse type. The successive bubble collapses after the collapse of main bubble were caused due to pressure wave near the flow field. For cavitation in a vibratory apparatus, cavitation bubbles on the vibratory disk surface were examined in detail, especially from the viewpoint of a non-cavitation ring. The disappearance of bubbles spread radially toward the outer region through the motion of vibratory horn.

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