The effect of a seasonal stratification variation on the load exerted by internal solitary waves on a cylindrical pile
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摘要: 本文基于Morison经验公式和模态分离估算孤立内波作用于圆柱作用力和力矩的方法(Cai et al., 2003; 2006),研究表明,对于南海大陆架上同一地点,即便孤立内波振幅相同,但孤立内波作用于圆柱载荷的大小也存在着明显的季节性变化。为此,通过一个三参数层结模式来研究水体层结对载荷的影响情况。结果表明,孤立内波作用于圆柱载荷的大小依赖于水体的层结程度。层结越强,作用力和力矩越大;当水体最大跃层深度变深,作用力减小但力矩增大;当水体跃层宽度变窄,作用力增大但力矩减小。这解释了南海四季孤立内波作用于圆柱载荷大小存在明显季节性变化的原因。Abstract: On the basis of Morison's empirical formula and modal separation method in estimating the force and torque exerted by internal solitary waves (ISWs) on a cylindrical pile, it is found that the loads exerted by the ISWs change largely in different seasons at the same site of the continental shelf in the South China Sea (SCS) even under the condition that the amplitudes of ISWs are the same. Thus, the effect of a seasonal water stratification variation on the force and torque exerted by the ISWs is investigated, and a three-parameter stratification model is employed. It is shown that the loads exerted by the ISWs depend largely on the water stratification. The stronger the water stratification, the larger the force and the torque;when the depth where the maximum thermocline appears is deepened, the force decreases but the torque increases;when the width of the thermocline is narrowed, the force increases but the torque decreases. The seasonal variation of the force and the torque exerted by the ISWs in four seasons in the SCS is thus explained.
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Key words:
- internal solitary waves /
- force /
- torque /
- water stratification /
- South China Sea
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