Hamburg 2001 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 40: Statistische Physik in biologischen Systemen II

DY 40.3: Vortrag

Donnerstag, 29. März 2001, 10:30–10:45, S 6

How snapping shrimp snap: through cavitating bubbles — •Detlef Lohse¹, Michel Versluis¹, Anna von der Heydt¹, and Barbara Schmitz² — ¹University of Twente, Department of Physics, P.O. Box 217, 7500 AE Enschede — ²Department of Zoology, TU München, Lichtenbergstr. 4, 85747 Garching

Alpheus heterochaelis (“the snapping shrimp”) generates noise so loud that it disturbes submarine communication. It was believed that the noise is generated when the claw rapidly closes and its two sides hit each other. However, in this work we show with the help of high speed video (40000 frames/second) and parallel sound detection with a hydrophone that the origin of the noise in fact is a collapsing cavitation bubble: When rapidly closing the pair of scissors, the shrimp emits a thin water jet so fast that a cavitation bubble develops. This collapses and on collapse, it emits the sound. Our optical and acoustical measurements are supplemented through a simple theoretical model of the proces, based on the Rayleigh-Plesset equation.