【作者】 叶卫富；

【导师】 虞聪达； 宋伟华；

【作者基本信息】 浙江海洋学院 ， 捕捞学， 2012， 硕士

【摘要】 浅海围网养殖是一种生态的、健康的海水养殖方式，围网设施与其它渔业工程一样，在海上敷设养殖生产时与风、浪、流等海洋水文因子发生作用，养殖效能和设施安全性能与其承受的水动力有关，因而研究围网及其主要构件在水流和波浪条件下的水动力性能，特别是浮绳式围网的框架纲、系泊纲的水动力特性是非常重要的。本研究是依据渔具力学和海洋工程力学等理论，结合围网敷设海域的基本条件和水文情况，参照围网实物设计，制作围网模型，进行波浪和水流的模型水槽试验研究，分析围网的水动力特性，并结合围网的水阻力理论计算研究了围网贴底防逃、系泊等性能。首先进行围网模型浮绳框架纲水动力特性的水槽试验。按照实际生产情况，根据田内渔具模型试验准则，设计、制作长宽高尺寸均为1m的浮绳式围网模型，选择预加张力系泊方法，在日本东京大学的动水槽进行模型试验，分析研究框架纲水动力的变化规律。试验工况为均匀流速和规则波浪，流速为10cm/s、20cm/s，周期为1.2s-2.0s（间隔0.2s），波高为9-25cm（间隔4cm）。试验结果：（1）在水流作用下，迎流纲和背流纲会随流速的变化而发生松弛和拉紧状态的变化，而侧向纲随着流速增大由松驰变为拉紧。（2）在水流和波浪共同作用下，框架纲上的水动力呈周期性、不对称变化，水动力变化周期大致和波浪的周期保持一致；在流速和波浪周期试验工况分别相同时，框架纲的水动力极值是随着波高的增加而呈线性增大，当流速为10cm/s时，迎浪纲水动力极值比背浪纲的要大，当流速为20cm/s时，情况正好相反；在相同波浪条件下，当流速由10cm/s变为20cm/s时，前端迎流纲处的水动力均降低，而两根侧向纲和后端背流纲处的水动力有较大增加。其次进行围网模型系泊纲水动力特性的水槽试验。同样采用预加张力系泊方法和依据田内准则，设计、制作周长为5.83m，高度为4.5m的围网模型，在浙江海洋学院渔具水动力静水槽进行波浪试验，研究分析系泊纲水动力的变化规律。试验波浪为规则波，在工况周期（1.0、1.26、1.42、1.68、2.0s）下，进行28种不同波高工况试验：围网系泊纲波浪力的变化与试验波相似，呈周期性、不对称变化；在同一周期下系泊纲波浪力极值随波高呈现线性增大变化，而波浪力与周期的关系较复杂；应用傅里叶变换等计算方法分析波浪力成分，围网波浪力成分主要由漂移力和2个激振力组成，与网箱的波浪力成分、网衣垂直与波浪方向时的波浪力成分组成相类似，同时对波浪力变化规律进行计算，其模拟结论和模型水槽波浪试验情况比较接近。最后按照渔具力学理论进行围网水动力计算。结合围网敷设条件、围网结构特征和主尺度，对围网进行水动力计算，分析围网贴底结构所承受的水动力。在极限工况且浮筒一半浸没在水中时，单位宽度网衣在海底处的最大张力为1654.14N，垂直方向的最大拉力为434.36N，为了能使网衣贴底防止鱼类从底部逃逸，提高围网下纲的抗拨性，则至少需要直径4.5cm的锚链用于下纲沉子贴底，确保围网海上安全生产。通过对围网水动力学的理论分析、水槽试验和理论计算，初步得出了浅海围网设施的水动力变化规律，为围网设计、制作、海上敷设和围网设施抗风浪能力、防逃性能等研究提供理论依据和技术支撑，也为渔具力学的发展提供了基础理论。更多还原

【Abstract】 Seine aquaculture in offshore is an ecological and healthy marine aquaculture model,which facilities are similar to other fisheries engineering, is responded by oceanhydrological factors such as winds, waves and currents when applied to production jobs. Itssecurity and productiveness are correlated with the hydrodynamics on the seine. Therefore,it is very important to study about the hydrodynamics on the seine and its main componentsunder the conditions of the currents and waves, for example, the hydrodynamiccharacteristics on the floating frame rope, mooring rope.Based on the fishing gear mechanics and marine engineering mechanics theory, themodel flume experiments of wave and current have been carried out according to the basicconditions and the hydrological conditions of the seine mooring area, reference to thephysical design and production of seine model. The hydrodynamic characteristics of theseine has been analyzed, the functions of the seine affixed on the bottom to preventescaping and mooring and so on have been presented by the theoretical calculation of waterresistance to the seine.First, the experiments of the hydrodynamic characteristics on seine floating ropes inframe have carried out. According to the actual production and model test on Tauti Ruler,the floating rope seine model (the dimensions of length, width and height are all one meter)was designed and producted. We have used the method of pre-tension mooring, carring outto study on the law of variation of frame outline hydrodynamic, in the flume in Universityof Tokyo, Japan. The uniform speeds of currents and regular waves are generated in theexperiment. The speeds of currents are l0cm/s and20cm/s, and the wave periods from1.2sto2.0s (0.2s interval), the wave height is from9to25cm (4cm interval). The conclusions ofthe experiment are presented as follows:(1) With the change of velocities，forward andbackward frame outline are changed by the state of relaxation and tension under the actionof currents, but the side of frame outline are changed from relaxation to tension with thecurrent increase.(2) The change of hydrodynamic on the frame outline is cyclical、asymmetric under the interaction of currents and waves, the hydrodynamic periods isconsistent with the wave period. The certain test conditions which both same in the currentvelocity and wave periods, maximum value of hydrodynamic force with four frame outlineincreases as the wave height increases, they show a linear relationship. When the velocityof current is10cm/s, the maximum value of hydrodynamic force in the forward frame outline large than the backward frame outline, when the velocity of current is20cm/s, thesituation is opposite. When the velocity of current from10cm/s to20cm/s, thehydrodynamic force of forward frame outline on the seine become lower. But thehydrodynamic force of two sides frames outline and backward frame outline become larger.Second, the experiments of the hydrodynamic characteristics on seine mooring ropesby model flume have been operated too. The pre-tension mooring method was selectedbased on the Tauti Ruler, the seine model (the perimeter is5.83m, height is4.5m) wasdesigned. This experiment was carried out wave testing to study on the law of variation ofmooring outline hydrodynamic, tested in Zhejiang Ocean University gearing hydrodynamicstatic flume. The test condition is wave periods (1.0s,1.26s,1.42s,1.68s and2.0s), a total is28different conditions, and the wave is regular wave. When the testing conditions aredifferent, the wave force on seine of the mooring outline changes periodically andasymmetrically, which is similar to the experimental waves. At the same period, themaximum wave force basically grows with the increasing of wave heights, while as to thewave periods, their correspondence is relatively complex. According Fourier transform tocalculate and analyze the ingredients of the wave force, which contains drift force and twomultiple exciting forces. It is similar to the composition of the cage wave force, the netwave force component that perpendicular to the wave direction. At the same time, thevariation regular of wave force was calculated，and the coincided results between thesimulation value and the experiment relatively was presented.Finally, we calculate seine hydrodynamic force in accordance with the fishing gearmechanics theory. Combing with the seine laying conditions, structural, features and themain dimensions, calculating seine hydrodynamic force, then analyzing the affixed bottomstructure to withstand the hydrodynamic forces on the seine. The pontoon completelysubmerged in water with in the limit conditions; the unit width of the net in the tension ofthe seabed is2222.17N. In order to enable net paste the bottom, prevent fish escaping fromthe bottom, and improve the following outline of seine anti allocated at least needs4.5cmdiameter anchor chain to affixed bottom the sinker for the following outline, to ensure thatseine production safety in ocean.Based on the theoretical analysis on the seine hydrodynamic, flume experiments andcalculations, the variation regular of the hydrodynamic force to the seine facility onoffshore were carried out, for designing, producing, laying on offshore with seine facilityand the study about seine facilities anti-wave ability, preventing escape characteristicprovide a theoretical basis and technical supports, as well as provide a basis for the development of fishing gear mechanics theory.更多还原