Flexible Porous Wave Barrier for Enhanced Wetlands Habitat Restoration
Publication: Journal of Engineering Mechanics
Volume 129, Issue 1
Abstract
A flexible porous wave barrier is proposed to increase the effectiveness of wetlands habitat restoration projects by protecting cordgrass seedlings from wave action during the critical initial stages of growth following planting. The barrier consists of a vertical porous membrane anchored to the sea bed and kept under tension by a small buoyant float. The structure is easily constructed, requires little maintenance, and may be deployed from a small boat without the need for specialized equipment or trained personnel. A numerical model is developed to assess the effectiveness of this structure as a barrier to wave action. The fluid motion is idealized as linearized, two-dimensional potential flow and the equation of motion of the structure is taken to be that of a one-dimensional beam of uniform mass per unit length subjected to a constant axial force. The boundary integral equation method is applied to the fluid domain, and the dynamic behavior of the structure is also described through an appropriate Green function. Numerical results are presented that illustrate the effects of the various wave and structural parameters on the wave reflection characteristics of the structure. Small-scale physical model tests have also been carried out in the University of Houston wavetank facility to validate the predictions of the numerical model. In general, good agreement was obtained between the theoretical and experimental reflection coefficients. It is found that for certain structural parameter combinations a porous tensioned membrane structure may provide a reasonably effective barrier in the short- to mid-wavelength range.
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References
Abul-Azm, A. G.(1994). “Wave diffraction by double flexible breakwaters.” Appl. Ocean. Res., 16, 87–99.
Aoki, S., Liu, H., and Sawaragi, T. (1994). “Wave transformation and wave forces on submerged vertical membrane.” Proc., Int. Symp. on Waves: Physical and Numerical Modeling, Vancouver, Canada, 1287–1296.
Chwang, A. T.(1983). “Porous wavemaker theory.” J. Fluid Mech., 132, 395–406.
Clough, R. W., and Penzien, J. (1975). Dynamics of structures, McGraw-Hill, New York.
Darwiche, M. K. D., Williams, A. N., and Wang, K. H.(1994). “Wave interaction with a semiporous cylindrical breakwater.” J. Waterw., Port, Coastal Ocean Div., Am. Soc. Civ. Eng., 120(4), 382–403.
Dean, R. G., and Dalrymple, R. A. (1985). Water wave mechanics for scientists and engineers, Prentice-Hall, Englewood Cliffs, N.J.
Galveston Bay Foundation. (1998). “Habitat conservation blueprint: Sites, strategies, and resources.”
Kee, S. T., and Kim, M. H.(1997). “Flexible membrane wave barrier. II: Floating/submerged buoy–membrane system.” J. Waterw., Port, Coastal Ocean Div., Am. Soc. Civ. Eng., 123(2), 82–90.
Kim, M. H., and Kee, S. T.(1996). “Flexible membrane wave barrier. I: Analytic and numerical solutions.” J. Waterw., Port, Coastal Ocean Div., Am. Soc. Civ. Eng., 122(1), 46–53.
Sawaragi, T., Aoki, S., and Yasui, A. (1989). “Tensions on silt curtains and currents in waves.” Proc., 8th Int. Conf. on Offshore Mechanics and Arctic Engineering, The Hague, Holland, 13–21.
Taylor, G. I.(1956). “Fluid flow in regions bounded by porous surfaces.” Proc. R. Soc. London, Ser. A, 234, 456–475.
Thompson, G. O., Sollitt, C. K., McDougal, W. G., and Bender, W. R. (1992). “Flexible membrane wave barrier.” Proc., Civil Engineering in the Oceans Conf. V, College Station, Tex., 129–148.
Twu, S. W., and Lin, D. T.(1991). “On a highly effective wave absorber.” Coastal Eng., 15, 389–405.
Wang, K. H., and Ren, X.(1993). “Water waves on flexible and porous breakwaters.” J. Eng. Mech., 119(5), 1025–1047.
Williams, A. N.(1993). “Dual floating breakwaters.” Ocean Eng., 20, 215–232.
Williams, A. N.(1996). “Floating membrane breakwater.” J. Offshore Mech. Arct. Eng., 118, 46–52.
Williams, A. N., Geiger, P. T., and McDougal, W. G.(1991). “Flexible floating breakwater.” J. Waterw., Port, Coastal Ocean Div., Am. Soc. Civ. Eng., 117(5), 429–450.
Williams, A. N., Geiger, P. T., and McDougal, W. G.(1992). “Submerged compliant breakwater.” J. Offshore Mech. Arct. Eng., 114, 83–90.
Williams, A. N., and Li, W.(1998). “Wave interaction with a semiporous cylindrical breakwater mounted on a storage tank.” Ocean Eng., 25, 195–219.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 129 • Issue 1 • January 2003
Pages: 1 - 8
Copyright
Copyright © 2003 American Society of Civil Engineers.
History
Received: Jun 1, 2001
Accepted: May 22, 2002
Published online: Dec 13, 2002
Published in print: Jan 2003
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