【作者】 黄六一；

【导师】 梁振林；

【作者基本信息】 中国海洋大学 ， 增殖养殖工程， 2013， 博士

【摘要】 随着我国渔业资源衰退以及国家对海洋经济发展和食品的需求，发展深水抗风浪网箱是我国海水养殖业可持续发展的一条必由之路。研究深水网箱设施的水动力性能是保护渔民的生命和财产安全的重要技术保障。本论文研究依托于国家“863”计划、国家自然科学基金项目。HDPE双浮管网箱是我国深水网箱最主要的种类，在目前我国6000多只深水网箱中，占到70%以上的份额。本文选取我国常用的周长40m、网深10m的HDPE圆形双浮管单体或网箱组（四个圆形网箱组成）作为研究对象，以水槽模型试验和海上实测为研究手段，运用渔具力学，波浪理论，海洋工程结构物与波流间作用理论以及电子信息等技术，结合理论分析和傅立叶数据处理方法，获得以下研究成果：1.采用田内模型准则与狄克逊模型准则在水槽中开展了单体圆形网箱模型水动力试验，检验二者试验结果的差异。结果表明，二者在一定流速范围内差异不大，均可作为水流中的网箱模型试验准则；网箱整体阻力、箱体阻力随着流速增加而增加，二者呈幂函数关系；阻力系数随着雷诺数增加而减小，二者也呈幂函数关系。2.获得了单个圆形网箱系统在正面或450受到流、波浪、波流作用下不同部位的缆绳张力分布。主要受力缆绳为前端缆绳（正面、450）、后侧缆绳（正面）和前侧缆绳（450）。3.采用傅立叶分析解析了最大缆绳张力中定常力、线性波浪力以及非线性波浪力的组成关系，获得了张力在波浪和波流中的组成特性。4.以固定点波高仪与张力同步测量数据推算出了网箱正面受波浪作用时，缆绳张力-时间曲线中特殊值点出现时刻，波峰、波谷在网箱系统上的位置。5.采用四阶傅立叶展开系数之和作为缆绳最大张力，通过数据分析，获得了缆绳张力与波高、周期等参数的关系；在波浪作用下（正面和450），缆绳最大张力与波高关系。6.通过无量纲分析，获得了缆绳最大张力无量纲量及其与波长网箱直径比、波陡之间的关系；采用正面波浪的缆绳最大张力-波高回归公式和最大张力无量纲与波陡回归公式推算正面波浪作用时的前端缆绳和后侧缆绳的在实际海况下的最大缆绳张力，将二者的结果进行比较，说明最大张力无量纲量可以用于此类网箱实际海况下的缆绳最大张力的推算；并推算出一系列海况下缆绳最大张力。7.根据对正面和450波浪和波流作用下单体网箱缆绳最大张力推算结果对进行比较，采用网箱正面受波浪流作用的锚泊方式优于450受波浪流的锚泊方式。8.获得了网箱组在波浪、波流中的缆绳最大张力的与波、流因子之间的关系，并推算出系列实际工况下网箱组的缆绳最大张力；实际波高2m-5m时，缆绳最大张力范围在48KN-199KN之间；实际流速31.6m/s，波高2m-5m时，最大缆绳张力在81KN-402KN之间。9.自主研发了一种用于海水中长时间测量网箱缆绳张力的自动记录式水下拉力计，在实际恶劣海况中进行了网箱部分缆绳的张力测试，验证了拉力计的可靠性，获得了实际海况中实物网箱浮框绳的张力变化，为实物网箱受力分析提供了第一手资料。本文中的缆绳最大张力无量纲量研究成果、水下自动记录式拉力计的开发和海上实测应用均具有明显的创新性，研究成果丰富了网箱水动力学研究体系，研究结果可为HDPE双浮管浮式网箱理论计算和设计提供参考依据。更多还原

【Abstract】 With the decline of fishery resources in China and increasing demand on sea foodtogether with growing marine economic, the development of deep-water anti-wave cages isan effective way to the sustainable development in domestic marine aquaculture industry.Studying on the hydrodynamic performance of deep-water cage facilities is an importanttechnical support to protect human lives and property for fishermen. The present dissertationis based on the researches of the National863High Technology Development Plan Projectand the National Natural Science Fund Project.HDPE sea-cage with double floating tubes is the most popular cages used in China,sharing more than70%of over6000cages totally. In the present work, model tests andfull-scale measurement on site are performed on the circular sea cages with perimeter40meters and height10meters, which are commonly used in China. The measured data areprocessed by means of FFT. The experimental results are then analyzed by applying fish gearmechanics and theory on the interaction of marine structures with waves. The followingfindings are obtained:1. To inspect the differences between the Tauti rules and Dickson rules, which arepopularly used in the hydrodynamic tests of fishery gears, model tests of single cage withcircular shape are carried out in the tank under these two rules respectively. The resultsindicate that both rules can be used as the rules of cage model tests with an exceptional littledifference in certain cases of flow. The resistance of the cage body or the whole cage systemis found to be a power function of the flow velocity. Similarly, the drag coefficient can beexpressed as a power function of the Reynolds number.2. Tensions in each cable that is mooring a single circular net-cage system sufferingcurrent, waves or a combination of current and waves are measured. The cage system isfacing or oblique in45degrees relative to the coming waves or (and) current. It is found thatthe mooring forces are mainly acting on the front-line (both in the cases of head and obliqueseas), the rear side-line (in head seas) or the front side-line (in oblique sea).3. Fourier analysis is applied to the maximum cable tension to obtain the components ofsteady force, the linear and nonlinear wave forces. It is helpful to understand thecharacteristics of tensions when suffering from action of waves or wave-current.4. By comparing to the record of a fixed wave height gage, the corresponding position of the wave crest (or trough) relative to the cage system can be deduced at the moment when aspecial value appears in the time history of tension for the cage models in head seas.5. The relationship between the cable tension and wave height, wave period or theother parameters is obtained through data analysis. The sum of the Fourier coefficients up tothe fourth-order is defined as the maximum tension of cables. The relationship between themaximum cable tension and wave height is investigated (both in the cases of head and obliqueseas).6. Through dimensionless analysis, the relationship between non-dimensional maximumtension and wave length normalized by cage diameter or wave steepness is obtained. Theregression formulae relating the maximum cable tension of the leading-line and back-line tothe wave height for the prototype of sea cages in actual head sea conditions, as well as therelationship between the non-dimensional maximum tensions and wave steepness, arededuced. Comparing both results showes that the non-dimensional maximum tension can beused to reckon the maximum cable tension of prototype cages in real sea under various seaconditions.7. By comparing the maximum cable tension under the action of both waves and currentin head and oblique seas, it is found that the mooring system facing the waves is better thanthe one oblique to the waves.8. The relationship between the maximum cable tensions and flow parameters is obtainedfor a group of cages moored in both waves and currents. The maximum cable tensions ofprototype grouped cages are evaluated under a series of real sea conditions., It is found thatthe maximum cable tension is in the range of48KN-199KN when actual wave height is2m-5m. On the other hand, the maximum cable tension is in the range of81KN-402KN whenvelocity of current is31.6m/s together with wave height of2m-5m.9. In addition, an underwater stress auto-recorder is independently developed, which canmeasure the tension of underwater cables in sea for a long time. Tests under severe seaconditions are carried out and which verify the reliability of the stress recorder. Besides, thevariation of tensions in floating ropes under bad sea conditions is obtained, which will be thefirst-hand data in the future force analysis for the sea cages system.The non-dimensional analysis of maximum cable tension, the development ofunderwater stress auto-recorder and full scale measurements on site are the main points of thepresent research. The results of the present research will enrich the hydrodynamic studies ofnet-cages and the findings will provide reference for theoretical calculations and designs ofthe HDPE sea-cages with double floating tubes.更多还原