Enhancement of oscillation amplitude of cavitation bubble due to acoustic wake effect in multibubble environment

Takuya Yamamoto; Sergey V Komarov

doi:10.1016/j.ultsonch.2021.105734

Enhancement of oscillation amplitude of cavitation bubble due to acoustic wake effect in multibubble environment

Ultrason Sonochem. 2021 Oct:78:105734. doi: 10.1016/j.ultsonch.2021.105734. Epub 2021 Aug 27.

Authors

Takuya Yamamoto¹, Sergey V Komarov²

Affiliations

¹ Graduate School of Environmental Studies, Tohoku University, Miyagi 980-8579, Japan; Department of Metallurgy, Graduate School of Engineering, Tohoku University, Miyagi 980-8579, Japan. Electronic address: t-yamamoto@tohoku.ac.jp.
² Graduate School of Environmental Studies, Tohoku University, Miyagi 980-8579, Japan; Department of Metallurgy, Graduate School of Engineering, Tohoku University, Miyagi 980-8579, Japan.

Abstract

Acoustic cavitation occurs in ultrasonic treatment causing various phenomena such as chemical synthesis, chemical decomposition, and emulsification. Nonlinear oscillations of cavitation bubbles are assumed to be responsible for these phenomena, and the neighboring bubbles may interact each other. In the present study, we numerically investigated the dynamic behavior of cavitation bubbles in multi-bubble systems. The results reveal that the oscillation amplitude of a cavitation bubble surrounded by other bubbles in a multi-bubble system becomes larger compared with that in the single-bubble case. It is found that this is caused by an acoustic wake effect, which reduces the pressure near a bubble surrounded by other bubbles and increases the time delay between the bubble contraction/expansion cycles and sound pressure oscillations. A new parameter, called "cover ratio" is introduced to quantitatively evaluate the variation in the bubble oscillation amplitude, the time delay, and the maximum bubble radius.

Keywords: Acoustic cavitation bubble; Acoustic wake effect; Multi-bubble system; OpenFOAM; Ultrasound; Volume of fluid method.