Volume 81, Number 3, February 2008
Article Number 38004
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
Published online 03 January 2008
EPL, 81 (2008) 38004
DOI: 10.1209/0295-5075/81/38004

Spontaneous generation of spiral waves by a hydrodynamic instability

M. Habibi1, 2, P. C. F. Møller1, N. M. Ribe3 and D. Bonn1, 4

1  Laboratoire de Physique Statistique, UMR 8550 CNRS, École Normale Supérieure - 24, rue Lhomond, 75231 Paris Cedex 05, France
2  Institute for Advanced Studies in Basic Sciences (IASBS) - Zanjan 45195-1159, Iran
3  Institut de Physique du Globe de Paris and Université de Paris-7, CNRS, Tour 14 - 2, place Jussieu, 75005 Paris, France
4  Van der Waals-Zeeman Institute, University of Amsterdam - Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands

received 25 April 2007; accepted in final form 4 December 2007; published February 2008
published online 3 January 2008

The coiling of a thin filament of viscous fluid falling onto a surface is a common and easily reproducible hydrodynamic instability. Here we report for the first time that this instability can generate regular spiral patterns, in which air bubbles are trapped in the coil and then advected horizontally by the fluid spreading on the surface. We present a simple model that explains how these beautiful patterns are formed, and how the number of spiral branches and their curvature depends on the coiling frequency, the frequency of rotation of the coiling center, the total flow rate, and the thickness of the spreading fluid film.

83.60.Wc - Flow instabilities.
47.54.-r - Pattern selection; pattern formation.
47.35.-i - Hydrodynamic waves.

© EPLA 2008