Robert Mettin: abstract philtrans

Spatiotemporal dynamics of acoustic cavitation clouds

U. Parlitz (1), R. Mettin (1), S. Luther (1), I. Akhatov (2), M. Voss (1), and W. Lauterborn (1)

(1) Drittes Physikalisches Institut, Universität Göttingen,
Bürgerstraße 42-44, D-37073 Göttingen, Germany

(2) Ufa Branch of Russian Acadamy of Sciences
K. Marx St. 6, Ufa, 450000, Russia


Abstract

Bubble clouds forming in an extended volume of liquid in acoustic cavitation show a slowly varying filamentary structure whose origin is still not completely understood. Experimental observations are reported which provide some characteristics of the phenomenon, such as bubble distributions and sound field measurements. A discussion of relevant physical interactions in bubbly liquids is comprised of wave dynamics, Bjerknes and drag forces, nucleation and coagulation. For describing the structure formation process, continuum and particle approaches are employed. In framework of the continuum model it is shown that homogeneous bubble distributions are unstable and regions with high bubble concentration emerge in the course of a self-concentration process. In the particle model all bubbles are treated as interacting objects which move in the liquid. This approach is complementary to the continuum model. It allows the inclusion of some particular features, for instance Bjerknes forces based on nonlinear bubble oscillations. Both models are discussed and results are compared with experimentally observed patterns.


Phil. Trans. R. Soc. Lond. A 357, 313-334 (1999).


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