Experiment and Plesset-type analysis of cavitation bubble dynamics in viscoelastic materials

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04905
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Fluid engineering
• Research Institution: Keio University
• Principal Investigator: Ando Keita 慶應義塾大学, 理工学部(矢上), 准教授 (30639018)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: キャビテーション / 気泡核 / 物質移動 / 気泡力学 / 超音波 / 粘弾性体

Outline of Final Research Achievements

A measurement technique in combination with theory and simulation was developed, which enables one to quantify statics and dynamics of cavitation bubbles in viscoelastic solids. Micron-sized bubble nuclei were produced by focusing laser pulses into a gelatin gel under dissolved-gas supersaturation and their size was controlled based on mass diffusion. Statics of these nuclei and ultrasound-induced dynamics of spherical cavitation bubbles were obtained from a series of visualization experiments with varying the nucleus size. Effects of viscoelasticity on nonlinear dynamics of spherical bubbles in the gel can be quantified, with comparison to nonlinear bubble dynamics model of Plesset type.

Free Research Field

熱流体工学

Academic Significance and Societal Importance of the Research Achievements

本研究で提案した超音波気泡の体積振動の可視化と気泡力学モデルの連成に基づく気泡周囲媒質の粘弾性特性の取得手法により，商用レオメータの計測限界（100 Hz程度）を大幅に超える高ひずみ速度下での粘弾性計測が可能となった．医療分野では，非侵襲の治療法として超音波が用いられており，高ひずみ速度下における粘弾性特性の取得は医療応用上も極めて重要と言える．