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Long waves through emergent coastal vegetation

Published online by Cambridge University Press:  14 October 2011

Chiang C. Mei*
Affiliation:
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
I-Chi Chan
Affiliation:
School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
Philip L.-F. Liu
Affiliation:
School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA Institute of Hydrological and Oceanic Sciences, National Central University, Jhongli, Taiwan, 32001
Zhenhua Huang
Affiliation:
Earth Observatory of Singapore and Department of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639398
Wenbin Zhang
Affiliation:
Earth Observatory of Singapore and Department of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639398
*
Email address for correspondence: ccmei@mit.edu

Abstract

We study the effects of emergent coastal forests on the propagation of long surface waves of small amplitude. The forest is idealized by an array of vertical cylinders. Simple models are employed to represent bed friction and to simulate turbulence generated by flow through the tree trunks. A multi-scale (homogenization) analysis similar to that for seepage flows is carried out to deduce the effective equations on the macro-scale. The effective coefficients are calculated by numerically solving the micro-scale problem in a unit cell surrounding one or several cylinders. Analytical and numerical solutions for wave attenuation on the macro-scale for different bathymetries and coastal forest configurations are presented. For a transient incident wave, analytical results are discussed for the damping of a leading tsunami. For comparison series of laboratory data for periodic and transient incident waves are also presented. Good agreement is found even though some of the measured waves are short or nonlinear.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

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