ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

5aPAb11. Experimental investigation of onset threshold for shape oscillations for air bubbles in 1g.

D. Felipe Gaitan

R. Glynn Holt

Jet Propulsion Lab., 4800 Oakgrove Dr., M.S. 183-401, Pasadena, CA 91109

Experimental observations of single bubble oscillations have yielded a wide variety of phenomena: periodic and period-doubled spherical oscillations; periodic, quasiperiodic and chaotic multimode shape oscillations; and, most recently, periodic, period-doubled, quasiperiodic, and chaotic sonoluminescence. In an effort to determine the effect of gravity on these phenomena, the acoustic pressure threshold for shape oscillations of single gas bubbles in a 1g environment was measured. The bubble sizes varied between 20 and 100 5-m radius, and were simultaneously levitated and driven acoustically at 20 kHz in water. Mie scattering was used to measure the bubble radius and to monitor its motion before and after the onset of surface instabilities giving rise to shape oscillations. A video imaging system was used to determine the mode of the shape oscillations. [Work supported by NASA.]