Spatial-temporal dynamics of cavitation bubble clouds in 1.2 MHz focused ultrasound field.
Cavitation bubbles have been recognized as being essential to many applications of ultrasound. Temporal evolution and spatial distribution of cavitation bubble clouds induced by a focused ultrasound transducer of 1.2 MHz center frequency are investigated by high-speed photography. It is revealed that at a total acoustic power of 72 W the cavitation bubble cloud first emerges in the focal region where cavitation bubbles are observed to generate, grow, merge and collapse during the initial 600 micros. The bubble cloud then grows upward to the post-focal region, and finally becomes visible in the pre-focal region. The structure of the final bubble cloud is characterized by regional distribution of cavitation bubbles in the ultrasound field. The cavitation bubble cloud structure remains stable when the acoustic power is increased from 25 W to 107 W, but it changes to a more violent form when the acoustic power is further increased to 175 W.
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, PR China.
Hong
H
Chen
Xiaojing
X
Li
Mingxi
M
Wan
D000162:Acoustics; D003198:Computer Simulation; D044085:Microfluidics; D008962:Models, Theoretical; D010781:Photography; D011312:Pressure; D013010:Sonication; D013997:Time Factors; D014465:Ultrasonics; D014463:Ultrasonography / Q000379:methods*