重力式深水网箱的抗台设计与水动力性能分析

Anti-typhoon Design and Hydrodynamic Performance Analysis of the Gravity Deep-water Fish Cage

针对重力式深水网箱抗台风能力较弱,容易出现浮架损坏、锚绳断裂和网衣严重变形等问题,以一典型重力式深水网箱为研究对象,结合传统网格式系泊,提出在底部附加系泊缆的新型抗台设计方案,基于势流理论和非线性有限元方法,建立网箱数值模型,在不同入射角和波高下,对比分析传统网格式和新型抗台式系泊的网箱系泊缆张力、浮架运动和网箱变形。数值计算结果表明:与传统网格式系泊相比,新型抗台式系泊的网箱水平偏移平均减小7.81%,垂直下沉增加59.71%,系泊缆最大张力降低26.61%,网箱体积剩余系数增加超过70%,明显高于网箱容积的破坏阈值。

Considering the low capability of gravity deep-water fish cage under the typhoon,it is easy to cause some serious problems such as damage of floating collar,break of anchor lines and large deformation of fish net.Taking a typical gravity deep-water fish cage as an example,a new anti-typhoon type of the fish cage attached mooring lines to the bottom was designed combining with the traditional grid type mooring.Based on the potential flow theory and nonlinear finite element method,the numerical model of the fish cage was established.Compared with the traditional grid type of fish cage,the mooring line tension,floating collar displacement and the net deformation of the new anti-typhoon type fish cage were analyzed under the different incident angles and wave heights.The results showed that the horizontal displacement of the floating collar is reduced by about 7.8%and the vertical displacement is increased by about 59.71%,the maximum tension of new anti-typhoon type fish cage is decreased by about 26.61%;meanwhile,the volume-holding coefficient of the new anti-typhoon design is increased by about 70%and it is obviously higher than the damage threshold of cage volume.