PERSPECTIVE OF COASTAL VEGETATION PATCHES WITH TOPOGRAPHY VARIATIONS FOR TSUNAMI PROTECTION IN 2D - NUMERICAL MODELING
PERSPECTIVE OF COASTAL VEGETATION PATCHES WITH TOPOGRAPHY VARIATIONS FOR TSUNAMI PROTECTION IN 2D - NUMERICAL MODELING
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二维数值模拟中地形变化的沿海植被斑块对海啸防护的视角
DOI：
10.2208/prohe.52.133
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Tanimoto
中科院分区：
文献类型：
--
作者：
N. Nandasena;N. Tanaka;K. Tanimoto
采用二维数值模拟的方法，研究了不同地面坡度条件下两种密集生长的海岸植被——香鸭草和木麻黄对海啸灾害的抵御效果。合理地改变植被斑块的尺度和斑块间的间距，以表征腹地可能存在的植被形态。两种植被的水力特性变化趋势相似。最大流速的减小幅度大于植被斑块后最大水深的减小幅度。在非常温和的地面坡度下，水平爬升长度随斑块大小的增加而减小，但当坡度变陡时，重力效应对水平爬升长度的影响大于植被效应。相对较大的斑块和狭窄的间隙被确定为破坏性形式。事实上，与裸地相比，海啸向陆地流动时，最大流速分别在缺口出口、缺口进口和缺口中部增加，向海上流动时，两个方向都增加。
Effectiveness of two types of densely grown coastal vegetation, namely Pandanus odoratissimus and Casuarina equisetifolia were investigated with different ground slopes, against a tsunami event in 2-D numerical simulation. Dimensions of vegetation patches and gap between them were changed rationally in order to represent possible vegetation shapes available on hinterland. Both vegetations showed similar trend of hydraulic properties variations. It was observed that reduction of maximum current velocity is higher than the reduction of maximum water depth behind vegetation patch. Horizontal run-up length is reduced with the patch size increases for very mild ground slope, but when slope becomes steep, gravity effect is dominant than vegetation effect on run-up length. Relatively big patches with narrow gap are identified as destructive forms. In fact maximum current velocity is increased at gap-outlet, gap-inlet and middle of the gap when tsunami flows landward, towards offshore and in both directions respectively compared to the bare land.