Underwater expansion wave focusing by reflecting at the air interface

K. Ohtani, T. Ogawa

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This paper reports a preliminarily experimental result of high-speed shadowgraph optical visualization of underwater expansion wave focusing by using a simple two-dimensional wedge model for understanding of shock wave interaction phenomena in simulated biomedical materials. Underwater shock wave generated by detonating a micro-explosive (10 mg silver azide pellet) in a small chamber. The generated underwater shock wave was interacted with a wedge shaped interface between water and air divided by a thin film, and an expansion wave was generated by reflection at the interface. The process of underwater expansion wave generation and focusing phenomena was visualized by shadowgraph method and recorded by ultra-high-speed framing camera. Underwater shock wave was reflected as an expansion wave from the interface between water and air at the both side and focused and then cavitation bubble was created by pressure decreasing at the expansion wave focusing area. The pressure histories were measured simultaneously with high-speed optical visualization by a needle type pressure sensor. At the focusing area, the pressure was decreased rapidly, the negative peak pressure was the lowest.

Original languageEnglish
Title of host publicationSelected Papers from the 31st International Congress on High-Speed Imaging and Photonics
EditorsTakeharu Goji Etoh, Hiroyuki Shiraga, Takeharu Goji Etoh
ISBN (Electronic)9781510611009
Publication statusPublished - 2017
Event31st International Congress on High-Speed Imaging and Photonics - Osaka, Japan
Duration: 2016 Nov 62016 Nov 10

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


Conference31st International Congress on High-Speed Imaging and Photonics


  • High-speed optical visualization
  • Micro explosive
  • Shadowgraph
  • Underwater expansion wave


Dive into the research topics of 'Underwater expansion wave focusing by reflecting at the air interface'. Together they form a unique fingerprint.

Cite this