Water waves generated by underwater landslides
Water waves generated by underwater landslides
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DOI：
10.7907/s3nh-ra23
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发表时间：
1997
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影响因子：
--
通讯作者：
P. Watts
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文献类型：
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作者：
P. Watts
水下滑坡产生的海浪威胁着峡湾头附近、水下峡谷头附近、河流三角洲附近和火山岛上的沿海社区。这项工作提供了一个彻底的分析二维水下滑坡产生的水波，使用实验，理论和计算手段。水下滑坡产生的水波振幅是滑坡长度、初始滑坡淹没度、从水平面测量的倾斜角、滑坡运动的特征距离、滑坡运动的特征持续时间和滑坡变形率的函数。无量纲造波机曲线从上述参数允许预测水波振幅。这些造波机曲线广泛地应用于水下物体的非定常运动所产生的水波，只要该运动仅由一个特征距离尺度和一个特征时间尺度控制。水波振幅预测可用于减灾研究。水下滑坡质心位置的解析解提供了滑坡运动的特征距离和时间尺度。在45度斜坡上的二维实验结果证实了固体块体滑坡的造波曲线作为无量纲几何量和所谓的Hammack数的函数的存在。Hammack数是水波生成问题的正确无量纲时间。如果知道块体滑坡的质心运动，则可以从造波曲线预测块体滑坡产生的水波振幅。解析解再现了固体块体和散体滑坡的质心运动。45 °斜坡上散体滑坡的实验结果表明，滑坡变形降低了水波振幅。因此，固体块体滑坡产生的水波提供了一个上限的几何形状和运动学相似变形滑坡产生的水波。给出了线性水波产生的准则，沿着给出了等深渠道中深（或长）波传播的准则。利用无粘流体动力学程序对水下滑坡产生的水波进行了数值模拟。计算结果与实验结果吻合较好。
Water waves generated by underwater landslides threaten coastal communities near heads of fjords, near heads of underwater canyons, near river deltas, and on volcanic islands. This work provides a thorough analysis of water waves generated by two-dimensional underwater landslides using experimental, theoretical, and computational means. Water wave amplitudes generated by an underwater landslide are a function of the landslide length, the initial landslide submergence, the incline angle measured from horizontal, the characteristic distance of landslide motion, the characteristic duration of landslide motion, and the landslide rate of deformation. Nondimensional wavemaker curves constructed from the aforementioned parameters allow water wave amplitudes to be predicted. These wavemaker curves apply broadly to water waves generated by unsteady motion of a submerged object provided the motion is governed by only one characteristic distance scale and one characteristic time scale. Water wave amplitude predictions can be used for hazard mitigation studies. An analytical solution of underwater landslide center of mass position in time provides the characteristic distance and time scales of landslide motion. Two-dimensional experimental results on a 45 degree incline confirm the existence of wavemaker curves for solid block landslides as a function of nondimensional geometrical quantities and what is called the Hammack number. The Hammack number is the correct nondimensional time for water wave generation problems. Water wave amplitudes generated by solid block landslides can be predicted from the wavemaker curves if the center of mass motion is known. The analytical solution reproduces the center of mass motion of solid block and granular material landslides. Experimental results of granular material landslides on a 45 degree incline show that landslide deformation reduces water wave amplitudes. Therefore, water waves generated by solid block landslides provide an upper bound on water waves generated by geometrically and kinematically similar deforming landslides. A criterion for the generation of linear water waves is given along with criteria for deep (or long) wave propagation down a constant depth channel. Simulations of water waves generated by underwater landslides were conducted with an inviscid fluid dynamics code. The waves simulated by the code agree reasonably well with experimental results.