Defect turbulence in a spiral wave pattern in the torsional Couette flow.
Our experimental study is devoted to the transition to defect turbulence of a periodic spiral wave pattern occurring in the flow between a rotating and a stationary disk. As the rotation rate Omega of the disk is increased, the radial phase velocity of the waves changes its sign: The waves that propagate first outward on average, then become stationary and finally propagate inward. As they become stationary, the nucleation of topological defects breaks the periodicity of the pattern. For higher Omega, more and more defects are generated in the flow pattern. This article presents the statistical study of this defect mediated turbulence.
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Institut de Recherche sur les Phénomènes Hors Equilibre, UMR 6594, CNRS, and Universités d'Aix-Marseille I et II, 49 rue F. Joliot-Curie, BP 146, Technopôle de Château-Gombert, 13384 Marseille Cédex 13, France.
Le Gal
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