Shock–induced collapse and luminescence by cavities

Abstract

Recent observations of the collapse of single bubbles or clouds of cavities trapped within stationary acoustic fields have shown the production of light and these phenomena have been dubbed single-or multiple-bubble sonoluminescence. The experimental observation of the variations in the bubble radius with time, with simultaneous measurement of the light emission from the bubble, shows short pulses of light correlated closely with the point of minimum radius of the bubble. Results will be presented showing experimental observations of light produced from shock-collapsed cavities. The role of shock waves generated within the bubble by the motion of the walls will be discussed with application to the shock-wave hypothesis proposed as one of the mechanisms responsible for sonoluminescence. The likely asymmetry of the process, as recently proposed, and the consequent presence of a high-velocity jet will also be discussed. The effect of such 'hot' cavities within an explosive matrix is investigated and results are presented. The collapse of a single bubble shows that light emission from the explosive matrix is due to reaction caused by hydrodynamic heating by jet impact, not due to conduction from heated gas during compression. Similar results are seen in arrays of collapsing cavities. The effects of close, inert particles are discussed and an example is given.

Shock-induced bubble jetting into a viscous fluid with application to tissue injury in shock-wave lithotripsy

“…In this case, the formation of local hot spots in the material by the dissipation associated with this jetting seems to increase the overall explosive sensitivity of energetic materials to shock-like mechanical impacts. 10,11 In tissues, this jetting has been hypothesized to be the mechanism of mechanical injury during lithotripsy ͑e.g., see the recent discussion of Klaseboer et al 12 ͒, and it is potentially the mechanism by which bubbles subjected to bursts of high-intensity focused ultrasound ͑HIFU͒ can erode tissue ͑e.g., Ref. 13͒.…”

The collapse of single bubbles and approximation of the far-field acoustic emissions for cavitation induced by shock wave lithotripsy

“…For even stronger incident shock waves, the jet velocity could reach up to 8000 ± 4000 m s −1 as observed experimentally by Bourne & Field (1991) in experiments of shock-induced collapse of a 2D cavity. In related studies, luminescence was also observed (Dear, Field & Walton 1988;Bourne & Field 1991;Field 1994;Leighton 1994;Bourne & Field 1999;Bourne & Milne 2003). The phenomena of high-speed jet impingement and blast wave emission from jet impact are relevant to SWL as probably the main mechanisms of adverse effects.…”

Influence of the nonequilibrium phase transition on the collapse of inertia nonspherical bubbles in a compressible liquid

“…Moreover, the jet velocity following the nonspherical bubble collapse induced by shock wave impingement reaches several km/s [2]. According to their researches, quite high pressure and temperature fields and quite fast liquid flow would be locally generated in cavitation flows where many vapor bubbles are generated with evaporation and some of them collapse; the shock waves generated from the collapsing bubbles interact with the surrounding vapor bubbles.…”