A HIGH-SPEED PHOTOGRAPHIC STUDY OF ULTRASONIC CAVITATION NEAR RIGID BOUNDARY

• Published in: Journal of Hydrodynamics Vol. 20; no. 5; pp. 637 - 644
• Main Authors: BAI, Li-xin, XU, Wei-lin, TIAN, Zhong, LI, Nai-wen
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.10.2008; Springer Singapore
• Subjects: cavity; Engineering; Engineering Fluid Dynamics; high-speed photography; Hydrology/Water Resources; Numerical and Computational Physics; Simulation; ultrasonic cavitation; visualization; 流体动力学; 空穴现象; 超声波; 高速摄影技术; visualization; ultrasonic cavitation; cavity; high-speed photography
• ISSN: 1001-6058; 1878-0342; 1000-4874
• DOI: 10.1016/S1001-6058(08)60106-7

This article investigated an existing steady pattern of collapse and rebound (disintegration and aggregation) of cavitation bubbles near rigid boundary in acoustic field. A deformation process of cavitation bubble was accomplished in two acoustic cycles, namely, a spherical bubble collapsed towards the boundary to its minimum volume and then rebounded and grew into a toroidal bubble (or two individual bubbles) in one acoustic cycle, and the toroidal bubble (or two individual bubbles) collapsed towards the center of ring to its minimum volume, and then rebounded into a spherical bubble in the next acoustic cycle. Inertia force plays a key role in the transition between these two states. The microjet produced during the collapse of spherical bubble and the shock wave produced during the collapse of toroidal bubble (or two individual bubbles) impacts the boundary alternately. A cavitation bubble operating in this pattern can thus be an effective corrosion mechanism of rigid boundary.