Hydrodynamics of a body floating in a two-layer fluid of finite depth. Part 2. Diffraction problem and wave-induced motions
Hydrodynamics of a body floating in a two-layer fluid of finite depth. Part 2. Diffraction problem and wave-induced motions
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DOI：
10.1007/s00773-005-0212-3
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发表时间：
2006-09
影响因子：
2.6
通讯作者：
M. Kashiwagi;I. Ten;M. Yasunaga
中科院分区：
文献类型：
--
作者：
M. Kashiwagi;I. Ten;M. Yasunaga
对一般浮体在有限水深两层流体中的线性化二维绕射问题进行了求解，并研究了相应的波浪诱导运动。在两层流体中，对于规定的频率，入射波以两种不同的波模式传播。因此，对于入射波的每种模式，必须分别计算波浪激振力和由此产生的运动。本文应用作者在第一部分中提出的边界积分方程法直接求出物体表面的绕射势（压力）。根据计算结果，研究了流体密度比和界面位置对物体上的波浪激振力和物体运动的影响，包括物体与界面相交的情况。利用绿色定理，通过系统的推导，从理论上推导出有限深度系统的所有可能的互易关系的显式形式，这些关系在数值上被证实是满足的，具有很好的精度。实验还使用水和异链烷烃油作为两种流体和路易斯形体进行。将横荡力、垂荡力和垂荡运动的实测结果与计算结果进行了比较，两者吻合良好。
A linearized two-dimensional diffraction problem in a two-layer fluid of finite depth was solved for a general floating body and relevant wave-induced motions were studied. In a two-layer fluid, for a prescribed frequency, incident waves propagate with two different wave modes. Thus the wave-exciting forces and resulting motions must be computed separately for each mode of the incident wave. The boundary integral equation method developed by the authors in the Part-1 article was applied to directly obtain the diffraction potential (pressure) on the body surface. With the computed results, an investigation was carried out on the effects of the fluid density ratio and the interface position on the wave-exciting forces on the body and the motions of the body, including the case in which the body intersects the interface. By a systematic derivation using Green's theorem, all the possible reciprocity relations were derived theoretically in explicit forms for a system of finite depth; these relations were confirmed to be satisfied numerically with very good accuracy. Experiments were also carried out using water and isoparaffin oil as the two fluids and a Lewis-form body. Measured results for the sway- and heave-exciting forces and the heave motion were compared with the computed results, and a favorable agreement was found.