J. Phys. II France 6 (1996) 1099-1110
Power Fluctuations in Turbulent Swirling FlowsR. Labbé1, 2, J.-F. Pinton1 and S. Fauve1
1 Laboratoire de Physique URA 1325 CNRS, École Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
2 Universidad de Santiago de Chile, Casilla 307, Correo 2, Santiago, Chile
(Received 13 July 1995, received in final form 22 March 1996, accepted 4 April 1996)
We report an experimental study of the temporal fluctuations of the total power injected in a swirling flow generated in the gap between two coaxial disks, counter-rotating at a fixed velocity. We use either a free geometry in air or a shrouded one, i.e. with the disks enclosed in a cylindrical vessel. We show that the fluctuations of the power injection are large in both cases (rms amplitude up to 10% of the mean value), but that their statistical properties are qualitatively different. When the flow is confined in a cylindrical vessel, we find that the PDF of the power fluctuations is strongly non-Gaussian and we study the correlations between the power fluctuations and the pressure field at the boundary.
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