ACOUSTIC RADIATION FORCE ON A BUBBLE DRIVEN ABOVE RESONANCE

The positions and sizes of stably levitated bubbles on the Earth in an acoustic standing wave have been measured for bubbles larger than resonance size. The equilibrium positions are sensitive to the radiation force on the bubble. The results are in good agreement with the radiation force approximation of Eller [J. Acoust. Sec. Am. 43, 170-171 (1968)] as well as that of the more general results of Crum and Prosperetti [J. Acoust. Sec. Am. 73, 121-127 (1983)] and Lee and Wang [J. Acoust. Sec. Am. 93, 1637-1640 (1993)]. Previous experimental studies have measured forces on bubbles of smaller than resonance size or have been concerned with forces on larger bubbles in nonequilibrium situations.