Issue
EPL
Volume 88, Number 2, October 2009
Article Number 20006
Number of page(s) 6
Section General
DOI http://dx.doi.org/10.1209/0295-5075/88/20006
Published online 04 November 2009
EPL, 88 (2009) 20006
DOI: 10.1209/0295-5075/88/20006

Experimental observation of trapped modes in a water wave channel

P. J. Cobelli1, V. Pagneux2, A. Maurel3 and P. Petitjeans1

1   Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR CNRS 7636, Ecole Supérieure de Physique et de Chimie Industrielles - Paris, France, EU
2   Laboratoire d'Acoustique de l'Université du Maine, UMR CNRS 6613, Université du Maine - Le Mans, France, EU
3   Laboratoire Ondes et Acoustique, Institut Langevin, UMR CNRS 7587, Ecole Supérieure de Physique et de Chimie Industrielles - Paris, France, EU

cobelli@pmmh.espci.fr

received 24 July 2009; accepted in final form 1 October 2009; published October 2009
published online 4 November 2009

Abstract
The fluid around a free surface piercing circular cylinder in a long narrow wave tank can exhibit a local oscillation that does not propagate down the channel but is confined to the vicinity of the cylinder. This is a manifestation of the so-called trapped modes, bound states in the continuum occurring in many situations in physics. In this letter, using Fourier Transform Profilometry, fully space time resolved measurements for the free surface deformation are obtained. The scattering characteristics of the cylinder and consequently the behavior of the trapped-mode frequency are determined.

PACS
03.65.Ge - Solutions of wave equations: bound states.
43.20.Ks - Standing waves, resonance, normal modes.
47.35.Lf - Wave-structure interactions.

© EPLA 2009