Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-27T18:32:32.988Z Has data issue: false hasContentIssue false

Experimental study on water-wave trapped modes

Published online by Cambridge University Press:  06 January 2011

P. J. COBELLI*
Affiliation:
Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR CNRS 7636, Ecole Supérieure de Physique et de Chimie Industrielles, 10 rue Vauquelin, 75231 Paris CEDEX 5, France
V. PAGNEUX
Affiliation:
Laboratoire d'Acoustique de l'Université du Maine, UMR CNRS 6613, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, France
A. MAUREL
Affiliation:
Laboratoire Ondes et Acoustique, Institut Langevin UMR CNRS 7587, Ecole Supérieure de Physique et de Chimie Industrielles, 10 rue Vauquelin, 75231 Paris CEDEX 5, France
P. PETITJEANS
Affiliation:
Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR CNRS 7636, Ecole Supérieure de Physique et de Chimie Industrielles, 10 rue Vauquelin, 75231 Paris CEDEX 5, France
*
Email address for correspondence: [email protected]

Abstract

We present an experimental study on the trapped modes occurring around a vertical surface-piercing circular cylinder of radius a placed symmetrically between the parallel walls of a long but finite water waveguide of width 2d. A wavemaker placed near the entrance of the waveguide is used to force an asymmetric perturbation into the guide, and the free-surface deformation field is measured using a global single-shot optical profilometric technique. In this configuration, several values of the aspect ratio a/d were explored for a range of driving frequencies below the waveguide's cutoff. Decomposition of the obtained fields in harmonics of the driving frequency allowed for the isolation of the linear contribution, which was subsequently separated according to the symmetries of the problem. For each of the aspect ratios considered, the spatial structure of the trapped mode was obtained and compared to the theoretical predictions given by a multipole expansion method. The waveguide–obstacle system was further characterized in terms of reflection and transmission coefficients, which led to the construction of resonance curves showing the presence of one or two trapped modes (depending on the value of a/d), a result that is consistent with the theoretical predictions available in the literature. The frequency dependency of the trapped modes with the geometrical parameter a/d was determined from these curves and successfully compared to the theoretical predictions available within the frame of linear wave theory.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Callan, M., Linton, C. M. & Evans, D. V. 1991 Trapped modes in two-dimensional waveguides. J. Fluid Mech. 229, 5164.CrossRefGoogle Scholar
Cobelli, P. J., Maurel, A., Pagneux, V. & Petitjeans, P. 2009 Global measurement of water waves by Fourier transform profilometry. Exp. Fluids 46, 10371047.Google Scholar
Evans, D. V., Levitin, M. & Vassiliev, D. 1994 Existence theorems for trapped modes. J. Fluid Mech. 261, 2131.CrossRefGoogle Scholar
Evans, D. V. & Linton, C. M. 1991 Trapped modes in open channels. J. Fluid Mech. 225, 153175.CrossRefGoogle Scholar
Evans, D. V. & McIver, P. 1991 Trapped waves over symmetric thin bodies. J. Fluid Mech. 223, 509519.Google Scholar
Evans, D. V. & Porter, R. 1997 a Near-trapping of water waves by circular arrays of vertical cylinders. Appl. Ocean Res. 19, 8389.CrossRefGoogle Scholar
Evans, D. V. & Porter, R. 1997 b Trapped modes about multiple cylinders in a channel. J. Fluid Mech. 339, 331356.CrossRefGoogle Scholar
Evans, D. V. & Porter, R. 1999 Trapping and near-trapping by arrays of cylinders in waves. J. Engng Math. 35, 149179.CrossRefGoogle Scholar
Evans, D. V. & Porter, R. 2002 An example of non-uniqueness in the two-dimensional linear water-wave problem involving a submerged body. Proc. R. Soc. Lond. A 454, 31453165.CrossRefGoogle Scholar
Granot, E. 2002 Emergence of a confined state in a weakly bent wire. Phys. Rev. B 65 (23), 233101.Google Scholar
Harter, R., Abrahams, I. D. & Simon, M. J. 2007 The effect of surface tension on trapped modes in water-wave problems. Proc. R. Soc. A 463, 31313149.Google Scholar
Huntley, D. A. & Bowen, A. J. 1973 Field observations of edge waves. Nature 243, 349365.CrossRefGoogle Scholar
Johnson, R. S. 2007 Edge waves: theories past and present. Phil. Trans. R. Soc. A 365, 23592376.CrossRefGoogle ScholarPubMed
Jones, D. S. 1953 The eigenvalues of ∇2u + λu = 0 when the boundary conditions are given in semi-infinite domains. Proc. Camb. Phil. Soc. 49, 668684.CrossRefGoogle Scholar
Kuznetsov, N. G. & McIver, P. 1997 On uniqueness and trapped modes in the water-wave problem for a surface-piercing axisymmetric body. Q. J. Mech. Appl. Math. 50 (4), 565580.Google Scholar
LeBlond, P. H. & Mysak, L. A. 1978 Waves in the Ocean. Elsevier.Google Scholar
Linton, C. M. & Evans, D. V. 1992 Integral equations for a class of problems concerning obstacles in waveguides. J. Fluid Mech. 245, 349365.CrossRefGoogle Scholar
Linton, C. M. & McIver, M. 2002 The existence of Rayleigh–Bloch surface waves. J. Fluid Mech. 470, 8590.Google Scholar
Linton, C. M. & McIver, P. 2001 Handbook of Mathematical Techniques for Wave/Structure Interactions. CRC Press.CrossRefGoogle Scholar
Linton, C. M. & McIver, P. 2007 Embedded trapped modes in water waves and acoustics. Wave Motion 45, 1629.CrossRefGoogle Scholar
Londergan, J. T., Carini, J. & Murdock, D. 1999 Binding and Scattering in Two-Dimensional Systems: Applications to Quantum Wires, Waveguides and Photonic Crystals. Springer-Verlag.Google Scholar
Maniar, D. H. D. & Newman, J. N. 1997 Waves diffraction by a long array of cylinders. J. Fluid Mech. 339, 309330.CrossRefGoogle Scholar
Maurel, A., Cobelli, P. J., Pagneux, V. & Petitjeans, P. 2009 Experimental and theoretical inspection of the phase-to-height relation in Fourier transform profilometry. Appl. Optics 48, 380392.CrossRefGoogle ScholarPubMed
Maurel, A., Pagneux, V. & Wesfreid, J. E. 1995 Mean flow correction as non linear saturation mechanism in instabilities. Europhys. Lett. 32 (3), 217222.Google Scholar
McIver, M. 1996 An example of non-uniqueness in the two-dimensional linear water wave problem. J. Fluid Mech. 315, 257266.CrossRefGoogle Scholar
McIver, M. 2000 Trapped modes supported by submerged obstacles. Proc. R. Soc. Lond. A 456, 18511860.CrossRefGoogle Scholar
McIver, M. & Porter, R. 2002 Trapping of waves by a submerged elliptical torus. J. Fluid Mech. 456, 277293.Google Scholar
McIver, P. 1991 Trapping of surface water waves by fixed bodies in channels. Q. J. Mech. Appl. Maths 44 (2), 193208.CrossRefGoogle Scholar
McIver, P. 2002 Wave interaction with arrays of structures. Appl. Ocean Res. 24, 121126.Google Scholar
McIver, P. & Evans, D. V. 1985 The trapping of surface waves above a submerged, horizontal cylinder. J. Fluid Mech. 151, 243255.Google Scholar
McIver, P., Linton, C. M. & McIver, M. 1998 Construction of Trapped Modes for Wave Guides and Diffraction Gratings. Proc. R. Soc. Lond. A 454, 25932616.Google Scholar
McIver, P. & McIver, M. 1997 Trapped modes in an axisymmetric water wave problem. Q. J. Mech. Appl. Math. 50 (2), 165178.Google Scholar
McIver, P. & McIver, M. 2006 Trapped modes in the water-wave problem for a freely floating structure. J. Fluid Mech. 558, 5367.Google Scholar
McIver, P. & Newman, J. N. 2003 Trapping structures in the three-dimensional water-wave problem. J. Fluid Mech. 484, 283302.Google Scholar
Pagneux, V. 2006 Revisiting the edge resonance for lamb waves in a semi-infinite plate. J. Acoust. Soc. Am. 120 (2), 649656.Google Scholar
Postnova, J. & Craster, R. V. 2008 Trapped modes in elastic plates, ocean and quantum waveguides. Wave Motion 45 (4), 565579.CrossRefGoogle Scholar
Protas, B. & Wesfreid, J. E. 2002 Drag force in the open-loop control of the cylinder wake in the laminar regime. Phys. Fluids 14 (2), 810826.CrossRefGoogle Scholar
Retzler, C. H. 2001 Trapped modes: an experimental investigation. Appl. Ocean Res. 23, 249250.Google Scholar
Stokes, G. G. 1846 Report on recent researches in hydrodynamics. In Report to 16th Meeting Brit. Assoc. Adv. Sci., Southampton, Murrey, London, pp. 120.Google Scholar
Takeda, M., Ina, H. & Kobayashi, S. 1982 Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry. J. Opt. Soc. Am. 72, 156.CrossRefGoogle Scholar
Takeda, M. & Mutoh, K. 1983 Fourier transform profilometry for the automatic measurement of 3-D object shapes. Appl. Opt. 22, 39773982.CrossRefGoogle ScholarPubMed
Ursell, F. 1951 Trapping modes in the theory of surface waves. Proc. Camb. Phil. Soc. 47, 1346–358.CrossRefGoogle Scholar
Ursell, F. 1952 Edge waves on a sloping beach. Proc. R. Soc. A 214, 7997.Google Scholar
Ursell, F. 1987 Mathematical aspects of trapping modes in the theory of surface waves. J. Fluid Mech. 183, 421437.CrossRefGoogle Scholar
Zernov, V., Pichugin, A. & Kaplunov, J. 2006 Eigenvalue of semi-infinite elastic strip. Proc. R. Soc. Lond. A 462, 12551270.Google Scholar

Cobelli supplementary material

Movie 1. Experimental results for the time-evolution of the free-surface deformation for a/d = 0.5 and f = 2.5 Hz, close to the experimentally determined resonant (trapped-mode) frequency. This movie is composed of a sequence of 100 instantaneous free-surface deformation fields, registered at an acquisition rate of 250 Hz. Configuration II was chosen because the cylinder being closer to the entrance makes the amplitudes larger, rendering the phenomenon more evident. Local height is linearly color-coded between red and blue, the former corresponding to elevations and the latter to depressions with respect to the free-surface at rest. With this convention, green is associated with undeformed regions. The scale of the colorbar is in mm.

Download Cobelli supplementary material(Video)
Video 416.9 KB

Cobelli supplementary material

Movie 1. Experimental results for the time-evolution of the free-surface deformation for a/d = 0.5 and f = 2.5 Hz, close to the experimentally determined resonant (trapped-mode) frequency. This movie is composed of a sequence of 100 instantaneous free-surface deformation fields, registered at an acquisition rate of 250 Hz. Configuration II was chosen because the cylinder being closer to the entrance makes the amplitudes larger, rendering the phenomenon more evident. Local height is linearly color-coded between red and blue, the former corresponding to elevations and the latter to depressions with respect to the free-surface at rest. With this convention, green is associated with undeformed regions. The scale of the colorbar is in mm.

Download Cobelli supplementary material(Video)
Video 210 KB

Cobelli supplementary material

Movie 2. Experimental results for the time-evolution of the linear component of the free-surface deformation around the phase singularity (whose position is made evident by a black point at the center of the frame). The corresponding parameters are: a/d = 0.5 and f = 2.5 Hz, close to the experimentally determined resonant (trapped-mode) frequency. This movie is composed of a sequence of 100 instantaneous free-surface deformation fields, registered at an acquisition rate of 250 Hz. Local height is linearly color-coded between red and blue, the former corresponding to elevations and the latter to depressions with respect to the free-surface at rest. With this convention, green is associated with undeformed regions. The scale of the colorbar is in mm.

Download Cobelli supplementary material(Video)
Video 497.2 KB

Cobelli supplementary material

Movie 2. Experimental results for the time-evolution of the linear component of the free-surface deformation around the phase singularity (whose position is made evident by a black point at the center of the frame). The corresponding parameters are: a/d = 0.5 and f = 2.5 Hz, close to the experimentally determined resonant (trapped-mode) frequency. This movie is composed of a sequence of 100 instantaneous free-surface deformation fields, registered at an acquisition rate of 250 Hz. Local height is linearly color-coded between red and blue, the former corresponding to elevations and the latter to depressions with respect to the free-surface at rest. With this convention, green is associated with undeformed regions. The scale of the colorbar is in mm.

Download Cobelli supplementary material(Video)
Video 161.1 KB