Experimental observation of near-heteroclinic cycles in the von Karman swirling flow
Résumé
The bifurcations and the nonlinear dynamics of the von Kármán swirling flow between exactly counterrotating disks in a stationary cylinder are experimentally investigated by means of visualizations and particle image velocimetry. A regime diagram of the different flow states is determined as a function of the height-to-radius ratio and the Reynolds number Re based on disks rotation speed and cylinder radius. Among the steady and time-dependent states found in the experiment, robust near-heteroclinic cycles, which link two unstable states of azimuthal wavenumber m = 2, are observed and characterized in detail for = 2. These are compared with the numerical findings of Nore et al. " The 1 : 2 mode interaction in exactly counter-rotating von Kármán swirling flow, " J. Fluid Mech 477, 51 2003, with a particular emphasis on the influence of the imperfection and the noise of the experimental setup.
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...