Adiabatic behavior of strongly nonlinear internal solitary waves in slope-shelf areas
Adiabatic behavior of strongly nonlinear internal solitary waves in slope-shelf areas
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DOI：
10.1029/2004jc002705
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发表时间：
2005-04
影响因子：
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通讯作者：
V. Vlasenko;L. Ostrovsky;K. Hutter
中科院分区：
文献类型：
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作者：
V. Vlasenko;L. Ostrovsky;K. Hutter
利用海岸海洋探测实验（COPE）的实验数据，从理论上研究了大振幅内孤立波（ISW）在坡架地形上传播的变换。考虑到观测波的强烈非线性（等温线位移与初始深度之比达到5），采用两种不同的方法进行波演化的理论研究：在完全非线性非流体静力方程组框架下的数值模拟和基于两层流体的长波方程的估计，波浪振幅不受任何限制。特别注意的是在缓慢倾斜的底部上，当ISW在传播过程中保存能量并保持与每个局部深度对应的稳定孤立波接近的参数时，波演变的绝热阶段。强isw沿传播路径绝热变化，直至其垂直尺度（振幅）与总水深相当。这种绝热过程通常在孤子达到其极限振幅时结束，之后发生导致湍流产生的破断过程。对于陡坡，简化的两层模型适用于研究浅化过程，其范围与研究平坦底上的稳定孤子大致相同。即使是相对平滑的分层，一些孤子参数，如速度和粒子峰值速度，也可以从两层模型中得到满意的估计。
[1] Transformation of large-amplitude internal solitary waves (ISW) propagating over slope-shelf topography is studied theoretically and with the use of the experimental data collected during the Coastal Ocean Probing Experiment (COPE). Taking into account a very strong nonlinearity of observed waves (the ratio of isotherm displacement to their initial depth reached a value of 5), two different approaches were employed for the theoretical investigations of the wave evolution: numerical simulations in the framework of a fully nonlinear nonhydrostatic system of equations and estimations based on a long-wave equation derived for a two-layer fluid without any restrictions on the wave amplitude. Special attention is paid to the adiabatic stage of the wave evolution over a gently sloping bottom when the ISW conserves its energy in the course of propagation and preserves the parameters close to a steady solitary wave corresponding to each local depth. Strong ISWs vary adiabatically along the path of propagation until their vertical scale (amplitude) becomes comparable with the total water depth. This adiabatic process typically ends when a soliton reaches its limiting amplitude, after which the breaking process occurs that leads to the generation of turbulence. For a sharp pycnocline, simplified two-layer models are applicable for the study of the shoaling process roughly within the same limits as for steady solitons over a flat bottom. Even for a relatively smooth stratification, some soliton parameters, such as its velocity and the peak particle velocity, can be satisfactorily evaluated from two-layer models.