Deformation of a single bubble in organic solutions by ultrasound

<jats:p>Behavior of a single bubble under an ultrasound resonant state in a hydrocarbon liquid such as n-dodecane or benzene was observed using a stroboscope and a charge-coupled device (CCD) camera. Although sonoluminescence was not confirmed because of bubble stability limitations, bubble deformation was observed at a situation of stability limitation. Deformation occurred when the bubble contracted to its minimum size. Numerical analyses of deformation growth by Rayleigh-Taylor instability of an oscillated bubble were carried out at the surface. The distortion amplitude of all degrees continued oscillating as the bubble expanded or contracted, and the oscillation frequency increased with the degree. The distortion amplitudes are amplified through the afterbounce by the resonance effect if the oscillation frequency of the distortion amplitude of some degree is approximately equal to the frequency of the afterbounce. The distortion amplitude of all degrees, except for amplified degrees, was dampened by the viscosity effect, and if the distortion amplitudes of all degrees were dampened, the bubble was considered to form a sphere and become stable. A phase diagram of stability of an oscillated bubble showed a function of an ambient bubble radius and the amplitude of forcing pressure.</jats:p>