### ASA 124th Meeting New Orleans 1992 October

## 5aPAa2. Scaling laws for sonoluminescence.

**Ritva Lofstedt
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Bradley P. Barber
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Seth Putterman
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*Phys. Dept., Univ. of California, Los Angeles, CA 90024
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The extremely nonlinear dynamics of bubble motion is described by the
Navier--Stokes equations of fluid mechanics, as coupled to the laws of heat
conduction and mass diffusion. In order to gain insight into the limitations of
the hydrodynamic theory of bubble collapse, scaling laws have been derived for
the maximum radius, collapse temperature, hot spot lifetime, collapse pressure,
and ambient radius in terms of the applied sound field and the assumption that
the bubble is a gas-filled cavity. In order to match the scaling laws to the
experimental observations of collapse temperature and flash width requires that
the Mach number for bubble motion exceed unity. In conclusion, a description of
sonoluminescence must include the properties of imploding shock waves. [Work
supported by the US DOE Division of Engineering and Geophysics; R. L. is
supported by an A.T.&T. fellowship.]