Y . Auregan A . Maurel V . Pagneux J . - F . Pinton ( Eds . ) Sound - Flow Interactions

Ultrasound as a Probe of Plasticity? The Interaction of Elastic Waves with dislocations

AGNES MAUREL, VINCENT PAGNEUX, FELIPE BARRA and FERNANDO LUND Laboratoire Ondes et Acoustique, UMR CNRS 7587, Ecole Supérieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75005 Paris, France Laboratoire d’Acoustique de l’Université du Maine, UMR CNRS 6613, Avenue Olivier Messiaen, 72085 Le Mans, France Departamento de F́ısica and CIMAT, Facultad de Ciencias F́ısicas y Matemáticas, Univ...

Flow dynamics and magnetic induction in the von-Karman plasma experiment

Different regimes for water wave turbulence.

We present an experimental study on gravity capillary wave turbulence in water. By using space-time resolved Fourier transform profilometry, the behavior of the wave energy density |η(k,ω)|(2) in the 3D (k,ω) space is inspected for various forcing frequency bandwidths and forcing amplitudes. Depending on the bandwidth, the gravity spectral slope is found to be either forcing dependent, as class...

Determination of Lamb mode eigenvalues.

An original method is presented to determine the complex Lamb wave spectrum by using a numerical spectral method applied to the elasticity equations. This method presents the advantage to directly determine complex wave numbers for a given frequency via a classical matricial eigenvalue problem, and allows the wave numbers to be determined at relatively high frequencies (i.e., corresponding to m...

Chaotic dynamos generated by a turbulent flow of liquid sodium.

We report the observation of several dynamical regimes of the magnetic field generated by a turbulent flow of liquid sodium (VKS experiment). Stationary dynamos, transitions to relaxation cycles or to intermittent bursts, and random field reversals occur in a fairly small range of parameters. Large scale dynamics of the magnetic field result from the interactions of a few modes. The low dimensi...