Shape oscillations of bubbles in water driven by modulated ultrasonic radiation pressure : observations and detection with scattered laser light

• Published in: The Journal of the Acoustical Society of America Vol. 93; no. 2; pp. 706 - 713
• Main Authors: ASAKI, T. J, MARSTON, P. L, TRINH, E. H
• Format: Journal Article
• Language: English
• Published: Woodbury, NY Acoustical Society of America 01-02-1993; American Institute of Physics
• Subjects: Acoustics; Brackish; Exact sciences and technology; Freshwater; Fundamental areas of phenomenology (including applications); Marine; Nonlinear acoustics, macrosonics; Physics; Optical interferometry; Bubble; Non linear acoustics; Levitation; Experimental study; Ultrasound; Particle trapping
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.405434

Steady-state quadrupole shape oscillations of air bubbles trapped in water were excited by amplitude modulation of the acoustic radiation pressure used for levitation. This method of exciting controlled shape oscillations may make possible noncontact dynamical measurements of the rheological properties of bubbles. Bubble sizes ranged from 1.6- to 12-mm diameter corresponding to observed quadrupole mode frequenices of 190 to 17 Hz. Small-amplitude oscillations were detected by interference of scattered laser light. Some larger amplitude oscillations were detected by the unaided eye or with a television camera. The structure of the acoustic field in the levitator needed for the levitation of large bubbles is discussed. In the absence of modulation the levitated bubbles had an oblate shape.