Numerical investigation of transient harbor oscillations induced by N-waves
Numerical investigation of transient harbor oscillations induced by N-waves
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N波引起的瞬态港口振荡的数值研究
DOI：
10.1016/j.coastaleng.2017.03.004
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发表时间：
2017
影响因子：
4.4
通讯作者：
Ma Xiaojian
中科院分区：
文献类型：
--
作者：
Gao Junliang;Ji Chunyan;Gaidai Oleg;Liu Yingyi;Ma Xiaojian
海啸是一种行波，其特征是靠近海岸线的幅度大，波长长。通常，第一对前导波是前导-仰角N波（LEN波）或前导-仰角N波（LDN波）。这些海浪通常是毁灭性的，对沿海基础设施造成严重破坏，甚至造成人员伤亡。在与海啸有关的各种自然灾害中，港口振荡是世界上最常见的灾害之一，它会导致停泊船舶的过度运动和港口内的系泊缆断裂。瞬态振荡的模拟完全非线性Boussinesq模型，FUNWAVE-TVD。入射N波包括TS型和MS型等腰LEN和LDN波。TS型和MS型N波分别对应于Tadepalli和Synolakis [1]以及Madsen和Schäffer [2]提出的波形表达式。本文着重研究了入射波振幅和波型对港内相对波能分布的影响。文中还讨论了各种入射波的最大爬高和最大爬低。为了比较，也考虑了孤立波激发的瞬态振荡。本文所采用的港口假定为狭长的等水深港口，港内自由面运动基本上是一维的，研究表明，对于给定的港口，对于本文所研究的入射波振幅和入射波型的范围，较大的海啸导致港内相对波能分布更均匀。LDN波引起的相对波能分布总是比LEN波引起的相对波能分布更均匀，而孤立波引起的相对波能分布比各种N波引起的相对波能分布更集中。当入射波振幅较大时，LDN波的最大爬高远大于孤立波的最大爬高，而LEN波的最大爬高远小于孤立波的最大爬高。
Tsunamis are traveling waves characterized by large amplitudes and long wavelengths close to the coastline. Often, the first couple of leading waves are either leading-elevation N-waves (LEN waves) or leading-depression N-waves (LDN waves). These waves are usually devastating, causing serious damage to coastal infrastructures or even human casualties. Among various natural disasters related to tsunamis, harbor oscillations are one of the most frequent disasters around the world, which can cause excessive movements of moored ships and rupture mooring lines inside the harbor.In this article, transient harbor oscillations induced by various incident N-waves are first investigated. The transient oscillations are simulated by a fully nonlinear Boussinesq model, FUNWAVE-TVD. The incident N-waves include the TS-type and MS-type isosceles LEN and LDN waves. The TS- and MS-type N-waves correspond to the waveform expressions proposed by Tadepalli and Synolakis [1] and Madsen and Schäffer [2], respectively. This paper focuses on the effects of the incident wave amplitude and its type on the relative wave energy distribution inside the harbor. The maximum runup and rundown of various incident waves are also discussed. For comparison, the transient oscillations excited by solitary waves are also considered. The harbor used in this paper is assumed to be long and narrow and has constant depth; the free surface movement inside the harbor is essentially one-dimensional.This study reveals that, for the given harbor, for the range of the incident wave amplitude and the incident wave types studied in this paper, the larger tsunamis lead to a more uniform relative wave energy distribution inside the harbor. The relative wave energy distributions induced by the LDN waves are always more uniform than those induced by the LEN waves, while the relative wave energy distributions induced by the solitary waves are more concentrated than those induced by the various N-waves. When the incident wave amplitude is relatively large, the maximum runups of the LDN waves are considerably larger than those of the solitary waves, while those of the LEN waves are much less than those of the solitary waves.