ASA 127th Meeting M.I.T. 1994 June 6-10

4aPA3. Resonance effects in axisymmetrically forced bubble oscillations.

R. Glynn Holt

Eugene H. Trinh

Microgravity Res. Group, MS 183-401, Jet Propulsion Lab., 4800 Oak Grove Dr., Pasadena, CA 91109

Large (0.02(less than or equal to)kR(less than or equal to)0.5) bubbles are levitated in a primary acoustic field, trapped slightly above the pressure nodes. A secondary, amplitude-modulated acoustic field is superimposed to directly force the axisymmetric shape modes at a variety of pressures and frequencies. By satisfying the condition for external resonance (when the external modulation frequency f[sub d] is nearly equal to one of the mode-number-dependent shape oscillation frequencies f[sub n], n=2,3,4,...) the possibility of coupling energy into the volume mode via internal resonance (when the volume mode frequency f[sub 0] is nearly an integral multiple of f[sub n]) is investigated. In particular, the viability for such an experiment in 1g at reduced ambient pressures is discussed. Finally, the possibility for performing such an experiment in 0g is discussed. [Work supported by NASA.]