| 摘要: |
| 采用四种网箱系泊方法，设计单点系泊网衣构件水槽波浪试验。试验构件由六种网衣和框架装配而成，试验工况是规则波，周期为0.7—2.0s，波高为50—250mm。构件在水槽中作来回周期性直线运动，当试验波浪周期较小时，构件的来回运动不明显，主要以波浪运动为主，水动力峰值大体上呈周期性均匀变化；而当周期较长、波高较高时，构件在水动力的作用下产生了与波向相反的长周期漂移运动，有较大振幅的位移、速度和加速度，诱发了水动力的最大值，水动力变化呈现峰值短周期不均匀变化、最大值长周期变化和零拉力周期变化的规律。试验结果显示，与波高参数类似，随着网衣特性系数d/a的增大，网衣构件的水动力也增大，而水动力最大值长周期、零拉力周期变化规律分别是减短和增长的。在周期1.21、1.41、1.61、1.82s情况下，网衣C构件单点系泊试验水动力最大值是固定系泊计算水动力最大值平均的1.706、1.826、2.125、2.236倍，最大达3.61倍，表明单点系泊在波浪条件下构件水动力有较大的增加。 |
| 关键词: 单点系泊 网衣构件 波浪试验 |
| DOI： |
| 分类号: |
| 基金项目:国家863高技术发展计划资助项目,2001AA623030号,2003AA623030号;中国海洋大学物理海洋实验室资助(2002—2004年);浙江省高校青年教师资助计划资助(2003—2005年) |
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| WAVE EXPERIMENT ON NETTING STRUCTURE WITH SINGLE POINT MOORINGS |
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SONG Wei-Hua1,2, LIANG Zhen-Lin3, ZHAO Fen-Fang3, HUANG Liu-Yi3, ZHU Li-Xin3, CHEN Bo-Hai4
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1.Fisheries College, Ocean University of China, Qingdao, 266003;2.Department of Marine Fisheries, Zhejiang Ocean University, Zhoushan, 316004;3.Fishery College, Ocean University of China, Qingdao, 266003;4.Physical Ocean Key Open Laboratory, Ministry of Education of China, Ocean University of China, Qingdao, 266003
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| Abstract: |
| Marine cage mooring usually have four ways similar to other ocean engineering structures. Mooring system in marine aquaculture is a very critical requirement to ensure stable and effective production. In terms of design and installation of the system, one must consider it as a function of a number of different structural and operational elements. This is particularly important in offshore mariculture field, where environmental loading may be intensive. Although waves and currents are major mechanic forces affecting those cages, research on them remains weak for lacking sufficient data of the forces. Internal factors of the cage, such as framework pattern (shape and size), and materials (rigid or flexible net and rope), must be taken into consideration in any simulation of the sort. A single point mooring in netting structure is simple and money saving, also advanced in the design of the same sort. Six types of the system in net and frame pattern were designed by the authors, and the experiments on the mooring system under regular-wave condition were performed. In our experiments, the range of wave periods was 0.7–2.0s; the wave height was 50–250mm. A flume simulation was performed in lab with periodical and linear back-and-forth movement. In short wave period, the movement was unconspicuous, and it was major affected by wave, the peaks hydrodynamic force on the structures changed periodically and symmetrically on the whole. When wave period was long, the structures were long-period variable motion against wave direct ion, the larger amplitudes of displacement, velocity, acceleration were produced, the structures maximum hydrodynamic force was brought out, the peaks force on the structures changed short period and asymmetrically, the maximum force changed longer-period, and its zero-force changed periodically respectively. The simulated results showed that: such as wave height, along with d/a increased, the structures hydrodynamic force also increased, but the longer-period of the maximum force changed was shortened and the zero-force changed period was lengthened respectively. In flume test, the four conditions were comprised which was period 1.21s, 1.41s, 1.61s, and 1.82s. The simulated results showed that under the condition, the magnitudes of hydrodynamic force have positive relationship to the wave height, the multiples of the maximum hydrodynamic force of the SPM experiment testing value to the fixed mooring calculated value were 1.706, 1.826, 2.125, and 2.236 for net C structure, and the maximum multiples reached 3.61, indicating that the impact of hydrodynamic force should be increased by SPM. In the some way, sea-cages mooring methods were selected according to the sea location conditions, for instance, the SPM method usually was laid in bay or shallow aquiculture zone. Therefore, the sea-cage may be moored in offshore when sunken depth to cage height and laid in bi-directional current. But this paper dealt with only the situation mentioned above, in the future, the mutual interaction of wave and current must be considered by using above methods similarly, and if the wave was irregular, the second-order even the third-order wave force need researching. |
| Key words: Single point moorings, Netting structures, Lab flume testing |
