Wave Attenuation by Coastal Forest
Coastal forests, a part of natural coastal ecosystem, have long been considered as an effective means on protecting coastal regions against wind waves, storm surges and tsunamis.To study the capability of coastal forests on dissipating incoming waves, Meiet al.(2011, 2014) introduced a theoretical approach that applies the multi-scale perturbation theory of homogenization (Mei and Vernescu 2010) to investigate the interactions of incident waves with an infinitely long forest belt.In this paper we extend the theoretical model to a coastal forest with an arbitrary shape.In general, a coastal forest can be composed of multiple forest patches of arbitrary shape as sketched in Fig.1.A forest patch can be further divided into several subzones based on different forest properties,such as vegetation type/species, planting pattern and porosity.Therefore, a subzone can be surrounded by other subzones and/or the open water region.Each subzone is then considered as a homogeneous forest region where a constant bulk eddy viscosity is assumed.With strong contrast between the typical wavelength and tree spacing,the multi-scale perturbation method is applied to separate the micro-and macro-scale.The flow motion in a micro-scale cell, with one or more cylinders inside, can be obtained by solving the boundary-value problem numerically.The macro-scale equations governing the wave propagation are wave equations with the complex coefficients computed from the cell problem solutions.To deal with forest patches and subzones with arbitrary shape, the boundary integral equation method (Liggett and Liu 1983) is employed with all the boundaries being discretized into line elements such that the macro-scale wave dynamics can be solved numerically.Two different types of incident waves are considered.Small-amplitude periodic waves are first used to model wind waves and their interactions with coastal forest.A transient wave with a soliton-like shape is then investigated.Under both conditions, the boundary integral formulations for a general forest subzone as well as the open water region are derived.Laboratory experiments for two special forest configurations, which were conducted at the University of Cantabria in Spain (Maza 2015), are used to validate the present model.
Philip, L.-F.Liu Che-Wei Chang Chiang C.Mei
School of Civil and Environmental Engineering, Cornell University, USA;Department of Civil and Envir School of Civil and Environmental Engineering, Cornell University, USA Department of Civil and Environmental Engineering, MIT, USA
国际会议
The Second Conference of Global Chinese Scholars on Hydrodynamics(第二届全球华人水动学学术会议)
江苏 无锡
英文
15-18
2016-11-11（万方平台首次上网日期，不代表论文的发表时间）