Simultaneous measurements of shock waves, sonoluminescence flashes, and high-speed video of cavitation in high-quality factor resonators at high static pressures.

Abstract

Violent cavitation activity has been observed in water under hundreds of bars static pressure using Impulse Devices spherical resonators. To better understand the extreme conditions inside and in the immediate vicinity of the collapsing bubbles, we simultaneously recorded multi-frame shadowgraph images, acoustic pressure, and sonoluminescence (SL) flashes from the bubbles. Images of bubbles and shock waves were captured using a V710 Phantom high-speed camera (400 000 frames/s). The tip of a fiber-optic probe hydrophone was positioned in the field of view of the camera to correlate acoustic pressure with shadowgraph images of shock waves and bubble dynamics. SL flashes were collected with two photomultiplier tubes (PMTs, Hamamatsu, 1-ns rise time). The PMTs had identical ultraviolet filters but different sensitivities to extend the dynamic range from a single to thousands of photons. Typically a single bubble was spontaneously nucleated at the center of the sphere. After the first collapse, the bubble reemerged as a cluster of bubbles. The relationships among the static pressure, driving acoustic amplitude, the maximum bubble size, SL flashes, and shock wave amplitude will be discussed and compared with numerical results obtained using the hydrocode HYADES. [Funded by Impulse Devices, Inc. ACPT contract W9113M-07-C-0178.]