Application of the Subharmonic Threshold to the Measurement of the Damping of Oscillating Gas Bubbles

Abstract

It is suggested that the damping affecting the forced radial oscillations of gas bubbles can be determined very accurately through the measurement of the subharmonic threshold for the oscillations. The advantage of the method is that, while the subharmonic oscillations have a large amplitude and can be easily detected, the theory can be accurately based on a perturbation approach. The theoretical basis for the subharmonic generation is also reviewed and its results illustrated for the case of an air bubble in water.