Revealing the dynamics of a bubble in acoustic cavitation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15000
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 21030:Measurement engineering-related
• Research Institution: 防衛大学校(総合教育学群、人文社会科学群、応用科学群、電気情報学群及びシステム工学群) (2021); Gifu National College of Technology (2019-2020)
• Principal Investigator: Kuroyama Takanobu 防衛大学校(総合教育学群、人文社会科学群、応用科学群、電気情報学群及びシステム工学群), 応用科学群, 講師 (40781737)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 音響キャビテーション / 気泡ダイナミクス / レーザ散乱 / 超音波ホーン

Outline of Final Research Achievements

The purpose of this study is to clarify the oscillation of acoustic cavitation bubbles generated in liquid by ultrasound. An optical system for measurement of the bubble oscillation was constructed. This system measures the bubble oscillation from the intensity change of scattered light generated by irradiating a laser beam onto the bubbles. We measured bubbles generated under an ultrasonic horn using the system. The results show that there are bubbles near the horn that exhibit vibrations similar to those of a single bubble, and the number of such bubbles decreases as the distance from the horn increases. It is also found that at all positions in the vicinity of the horn, a large percentage of the bubbles oscillate differently from single bubble.

Free Research Field

強力超音波

Academic Significance and Societal Importance of the Research Achievements

本研究では音響キャビテーション中の気の一つ一つの振動を計測する手法を確立した．計測結果は機械学習の手法を用いて解析を行うことが容易であり，これまで解析が困難であった気泡振動のばらつきの評価を可能とする．また本手法により得られた計測結果は，化学汚染物質除去等の音響キャビテーションの応用研究を進める上で重要な知見を与えるものである．