title: The final stage of the collapse of a cloud of bubbles close to a rigid boundary.
abstract: The final stage of the collapse of a hemispherical cloud of bubbles close to a rigid boundary was investigated by ultra high-speed photography with up to 200 million frames/s. Our investigations reveal two types of secondary shock wave emission during cloud rebound. In the first case, the secondary shock wave emission is a consequence of the free collapse of a bubble within the cloud by the ambient pressure in the fluid. In the second case, it is a consequence of the interaction of the cloud-collapse-induced shock wave with microbubbles situated close to the collapse site of the cloud. The latter can be very powerful, resulting in a secondary shock wave emission with a maximum amplitude of about 0.5 GPa.
authors.affiliation: Department of Hydraulics, University Politehnica, 060042 Bucharest, Romania. eabrujan@yahoo.com
authors.forename: E A
authors.initials: EA
authors.lastname: Brujan
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
authors.forename: K
authors.initials: K
authors.lastname: Yoshinaka
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumoto
mesh_terms: D000535:Aluminum / Q000737:chemistry; D005740:Gases / Q000737:chemistry*; D013499:Surface Properties; D014465:Ultrasonics; D014867:Water / Q000737:chemistry
chemical_list: D005740:Gases; D014867:Water; D000535:Aluminum