Introduction

Our research efforts are aimed at understanding complex multiscale physics of multiphase media such as cavitating liquids and soft matter. We develop experimental, theoretical, and numerical methods to reveal the dynamics of cavitation bubbles. With fundamental understandings of cavitation and bubble dynamics, we target contributions to industrial applications including ultrasonic cleaning, microbubble aeration, medical application, food processing, and underwater explosions (UNDEX).

■Medical Application of ultrasonic bubbles and laser bubbles
・Research Objective: Experimental analysis of viscous effects on shock waves propagating in highly viscous fluid such as human tissue
- Title: Ultra-high-speed photography and hydrophone measurement of laser-induced shock waves in liquids: Viscous effects on spherical shock dynamics, H. Kurahara, K. Ando, Journal of the Society of Rheology, Japan 52, 313-321 (2024).
・Research Objective: Rheological measurement of gel with ultrasound-induced bubble oscillation
- Title: Ultrasound-induced nonlinear oscillations of a spherical bubble in a gelatin gel, K. Murakami, Y. Yamakawa, J.Y. Zhao, E. Johnsen, K. Ando, Journal of Fluid Mechanics 924, A38 (2021).
・Research Objective: Rheological measurement of gel elasticity with a bubble growing under dissolved-gas supersaturation
- Title: Quasistatic growth of bubbles in a gelatin gel under dissolved-gas supersaturation, K. Ando, E. Shirota, Physics of Fluids 31(11), 111701 (2019).
・Research Objective: Measurement of cavitation inception pressure by vizualization of shock-bubble interaction
- Title: Cavitation bubble nucleation induced by shock-bubble interaction in a gelatin gel, R. Oguri, K. Ando, Physics of Fluids 30(5), 051904 (2018).

■Physical cleaning with acoustic cavitation bubbles
・Research Objective: Experimental determination of opitimal injection distance for ultrasonic flow cleaning performance to be maximal
- Title: Optimal injection distance in ultrasonic water flow cleaning, K. Ando, R. Sakota, H. Usui, T. Ishibashi, H. Matsuo, K. Watanabe, Solid State Phenomena 346, 258-262 (2023).
・Research Objective: Experimental analysis of the role of cavitation bubbles in ultrasonic flow cleaning
- Title: Particle removal in ultrasonic water flow cleaning: Role of cavitation bubbles as cleaning agents, K. Ando, M. Sugawara, R. Sakota, T. Ishibashi, H. Matsuo, K. Watanabe, Solid State Phenomena 314, 218-221 (2021).
・Research Objective: Development of efficient and damage-free ultrasonic cleaning methods with gas-supersaturated water
- Title: Low-intensity ultrasound induced cavitation and streaming in oxygen-supersaturated water: Role of cavitation bubbles as physical cleaning agents, T. Yamashita, K. Ando, Ultrasonics Sonochemistry 52, 268–279 (2019).
・Research Objective: Quantification of microbubble aeration performance
- Title: Aeration of water with oxygen microbubbles and its purging effect, T. Yamashita, K. Ando, Journal of Fluid Mechanics 825, 16–28 (2017).

Areas of Research

・Medeical treatment with ultrasonic bubbles (lithotripsy, cancer treatment)
・Ultrasonic cleaning
・Rheological mesurement with microbubble oscillation

Social Contributions

・Advancement in ultrasound-based medical treatment techniques
・Advancement in performance of ultrasonic cleaning techniques (high cleaning efficiency, damage-free cleaning)
・Better understanding of fluid flow and acoustic phenomena with visualization experiments