【作者】 郑艳娜；

【导师】 董国海； 滕斌；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2006， 博士

【摘要】 为了解决社会对水产品需求增长和浅水养殖业所存在问题间日趋突出的矛盾，“深水养殖网箱的研究”被列入中国第十个五年计划中的一个重点项目。本文对此研究项目中的两种浮式结构物在波浪作用下的水动力特性进行了物理模型试验和数值计算研究。一种结构是深水重力式网箱的圆形浮架结构，另一种是浮式防波堤结构。 对浮架结构的研究方面，首先针对重力式网箱浮架的运动进行了实验室物理模型试验，先后设计了两种锚碇结构形式—折线形和直线形，对每种锚碇—浮架系统分别量测了浮架上特定点的运动轨迹以及海底锚碇点的受力历时曲线。其次在时域内对浮架结构的运动和锚碇点受力进行了数值模拟。考虑到浮架结构的尺寸特点，采用改进的Morison公式计算波浪对浮架的作用力，简化计算的同时也面临着公式中水动力系数选取的难题，本文对流阻力系数等对浮架运动的影响进行了比较分析。锚碇系统的作用力计算需要考虑锚碇系统的动态响应，根据各段锚绳张力连续的条件求解各个时刻锚绳的运动及其产生的张力。在计算出浮架受力之后通过求解刚体运动方程得到浮架结构的刚体加速度、速度和位移，进而计算下一时刻的受力，使得计算得以连续进行下去，运动方程采用四阶Runge—Kutta方法求解。通过数值结果与试验结果的比较，验证本文数值模型的正确性，为浮架结构的深入研究和整体网箱的设计提供了技术支持。 浮式防波堤的结构形式很多，本文首先选取单箱、双箱和板式浮堤进行消浪性能试验，锚链在平衡状态有一定的拖地长度，对两种拖地长度进行了比较，分析了链长对浮堤消浪性能的影响。为了能有效的削弱长波，本文进而提出了一种板—网式浮式防波堤，并对浮堤的堤宽、网数和刚度以及波浪和水流的方向等因素对浮堤消浪性能的影响进行了物理模型试验。试验结果表明结构简单的板—网式浮防波堤能够起到一定的为深水网箱消浪的作用，是一种较为经济实用的浮式防波堤，具有一定的工程应用前景。 对浮式防波堤的数值模拟采用时域边界元方法，建立了时域边界积分方程。物体在波浪中运动的时候，物体的运动决定了所受流体作用力的大小，反过来，受力又影响了物体的运动，因此，边界积分方程和物体运动方程是相互耦合的，需要同时进行求解。运动方程同样采用四阶Runge—Kutta方法求解。浮堤的锚泊系统采用静态悬链线法模拟。本文对单箱、双箱和板式的浮式结构物进行了数值计算，结果表明对固定物体的模拟结果与解析解或频域解的吻合程度较好，计算得到的系泊浮堤透射系数随波浪周期的变化趋势与试验结果相一致。更多还原

【Abstract】 The development of the fish cage has become more and more important for human beings, and a lot of achievements have been obtained in the field of aquacultural engineering. However, moving marine aquaculture from near-shore region into deep-sea has become imperative mainly due to the environmental protection and the coastal utilization problems. Generally speaking, the advantages of developing the deep-sea aquaculture outweigh the disadvantages. However, some troubles have become more serious, such as the heavier waves and/or current forces on the whole system of the fish cage, and the systematic and thorough research into the fish cage system in deep water is a task of top priority. As a result, a national 863 high technology project has been initiated to develop basic research on the hydrodynamics of deep-sea cages. Two kinds of floating structures involved in the project are studied experimentally and numerically. One is the circle float collar of the gravity fish cage, and the other one is the floating breakwater.Having chosen a typical gravity fish cage with the fold-line or the straight-line mooring system, the experiment focuses on the research into movement of the generalized float collar and the tension of the mooring ropes. The numerical simulation is conducted in the time domain. Considering the size of the collar, the wave forces are calculated by the Morison equation, but in the equation the drag coefficient which is affected by many factors is difficult to determine, so in this dissertation the effect of the drag coefficient on the collar displacement is studied. The dynamic response of the mooring rope is considered in the mooring force calculation at every moment. The movement equation of the rigid body is solved to obtain the acceleration, the velocity and the displacement by the fourth order Runge-Kutta method. The comparison of the experimental data and the computational results has testified that the computational method can correctly predict the movement of the float collar and the tension of the mooring ropes.In order to find simple, cheap and effective type of floating breakwaters for open ocean aquaculture engineering, this dissertation introduces three types of structures: the Single-box, the Double-box , the Board and the Board-net. Two-dimensional physical model tests were conducted in a wave-current flume in laboratory to measure the transmission coefficient of these floating breakwaters under regular waves with or without currents. Based on an initial comparison of the wave transmission coefficients, the Board-net floating breakwater was proposed for the project, and detailed experiments were then conducted to examine the effects of several factors on wave transmission coefficient of this type of breakwater including the width of the board, the rows of net, the rigidity of the board, the current velocity, etc. The experimental results show that the Board-net floating breakwater, which is a simple and cheap更多还原