演 講 公 告

講題：Effects of Hydraulic Conductivity of Coastal Forest on Wave Propagation and Attenuation 
 

主講人：劉立方院士

中央大學水文與海洋科學研究所講座教授 

時間：9月7日（星期一）上午10點

地點：中央大學科學一館S-325教室

摘要：

　　Using multi-scale (homogenization) analysis, the effects of emergent coastal forests on the obliquely incident long waves are studied. Each tree unit in the forest is idealized by a group of vertical cylinders of different sizes and different arrangements, and the coastal forest consists of a series of tree units in a periodic pattern. A mixing length model is used to calculate the eddy viscosity generated by turbulent flow through the cylinders. The multi-scale analysis deduces the shallow water equations on the wavelength-scale. The effective coefficient in these equations is the equivalent hydraulic conductivity, which is a second-order tensor and is calculated numerically by solving the tree-scale problem in a unit cell that surrounds one or several cylinders with different diameters. Hydraulic conductivity depends on incident wave conditions, porosity, and configuration of the cylinders. For obliquely incident waves, analytical solutions for wave reflection, refraction, and attenuation are presented for different coastal forest configurations. The effects of hydraulic conductivity on the wave-forest interaction process are identified and discussed.