Hostname: page-component-77c89778f8-vpsfw Total loading time: 0 Render date: 2024-07-20T08:10:10.306Z Has data issue: false hasContentIssue false
  • English
  • Français

Wave absorbing system using inclined perforated plates

Published online by Cambridge University Press:  11 July 2008

I. H. CHO  and
M. H. KIM
I. H. CHO
Affiliation:
Department of Marine Industrial Engineering, Cheju National University, Jeju 690-756, Korea
M. H. KIM
Affiliation:
Department of Civil Engineering, Texas A&M University, College Station, TX 77843, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

The interaction of oblique monochromatic incident waves with horizontal/inclined/dual porous plates is investigated in the context of two-dimensional linear potential theory and Darcy's law (the normal velocity of fluid passing through a thin porous plate is linearly proportional to the pressure difference across it). The developed theory is verified by both small-scale and full-scale experiments. First, matched eigenfunction expansion (MEE) solutions for a horizontal porous plate are obtained. The relationship between the plate porosity and the porous parameter is obtained from systematic model tests by using six porous plates with different sizes and spacing of circular holes. Secondly, a multi-domain boundary-element method (BEM) using simple-sources (second-kind modified Bessel function) is developed to confirm the MEE solutions and to apply to more general cases including inclined or multiple porous plates. The BEM-based inner solutions are matched to the eigenfunction-based outer solutions to satisfy the outgoing radiation condition in the far field. Both analytical and BEM solutions with the developed empirical porous parameter agree with each other and correlate well with both small-scale data from a two-dimensional wave-tank test and full-scale measurement in a large wave basin. Using the developed predictive tools, wave-absorption efficiency is assessed for various combinations of porosity, water depth, submergence depth, wave heading, and plate/wave characteristics. In particular, it is found that the performance can be improved by imposing the proper inclination angle near the free surface. The optimal porosity is near porosity P=0.1 and the optimal inclination angle is around 10° as long as the plate length is greater than 20% of the wavelength. Based on the selected optimal parameters (porosity=0.1 and inclination angle=11.3°), the effective wave-absorption system for MOERI's square basin is designed.

Type
Papers
Information
Journal of Fluid Mechanics , Volume 608 , 10 August 2008 , pp. 1 - 20
Copyright
Copyright © Cambridge University Press 2008

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

Brebbia, C. A. & Dominguez, J. 1992 Boundary Elements an Introductory Course. McGraw-Hill.Google Scholar
Cho, I. H. & Kim, M. H. 1998 Interactions of a horizontal flexible membrane with oblique waves. J. Fluid Mech. 367, 139–161.CrossRefGoogle Scholar
Cho, I. H. & Kim, M. H. 1999 Wave deformation by a submerged flexible circular disk. Appl. Ocean Res. 21, 263–280.CrossRefGoogle Scholar
Chwang, A. T. 1983 A porous wavemaker theory. J. Fluid Mech. 132, 395–406.Google Scholar
Chwang, A. T. & Wu, J. 1994 Wave scattering by submerged porous disk. J. Waterway Port Coastal Ocean Engng 120, 2575–2587.Google Scholar
Evans, D. V. 1990 The use of porous screens as wave dampers in narrow wave tank. J. Engng Maths 24, 203–212.Google Scholar
McIver, M. 1985 Diffraction of water waves by a moored, horizontal, flat plate. J. Engng Maths 19, 297–320.Google Scholar
Mansard, E. P. D. & Funke, E. R. 1980 The measurement of incident and reflected spectra using a least squares methods. Proc. Coastal Engng 154–172.CrossRefGoogle Scholar
Mei, C. C., Liu, P. L.-F. & Ippen, A. T. 1974 Quadratic loss and scattering of long waves. J. Waterway Port Coastal Ocean Engng 100, 217–239.Google Scholar
Ouellet, Y. & Datta, I. 1986 A survey of wave absorbers. J. Hydraul. Res. 24, 265–280.Google Scholar
Siew, P. F. & Hurley, D. G. 1977 Long surface waves incident on a submerged horizontal plate. J. Fluid Mech. 83, 141–151.Google Scholar
Tuck, E. O. 1975 Matching problem involving flows through small holes. Adv. Appl. Mech. 15, 89–158.Google Scholar
Twu, S. W. & Lin, D. T. 1991 On a highly effective wave absorber. Coastal Engng 15, 389–405.Google Scholar
Wu, J. H., Wan, Z. & Fang, Y. 1998 Wave reflection by a vertical wall with a horizontal submerged porous plate. J. Ocean Engng 25, 767–779.Google Scholar
Yip, T. L. & Chwang, A. T. 2000 Perforated wall breakwater with internal horizontal plate. J. Engng Mech. 126, 533–538.Google Scholar
Yu, X. P. & Chwang, A. T. 1993 Analysis of wave scattering by submerged disk. J. Engng Mech. 119, 1804–1817.Google Scholar
Yu, X. P. & Chwang, A. T. 2002 Functional performance of a submerged and essentially horizontal plate for offshore wave control: a review. Coastal Engng J. 44, 127–147.Google Scholar