Application of piezoelectric PVDF film to the measurement of impulsive forces generated by cavitation bubble collapse near a solid boundary

Abstract

The use of piezoelectric polyvinylidene fluoride (PVDF) polymer film in high amplitude and fast dynamic measurements has grown increasingly. In this work we investigate the impulsive forces generated by the collapse of a cavitation bubble near a solid boundary using a 28 μm thick PVDF piezoelectric film. A pendulum-typed ball impact technique is designed to calibrate the film. The bandwidth and the resonant frequency of the PVDF film are determined using a gas dynamic shock tube. The growth and collapse of the bubble are photographed using a CCD camera. For a range of the proximity parameter γ (the ratio of the distance the bubble is created from the boundary to the maximum bubble radius), we record the impulsive forces generated by the bubble collapse. The features and the possible mechanisms of the impulsive forces are discussed. The high sensitivity, good durability, and large bandwidth of the PVDF film indicate its applicability in high amplitude impulsive field measurements.