浮式鲆鲽类网箱在波流场中动态响应的数值模拟

NUMERICAL SIMULATION OF FLOATING FLATFISH CAGE BEHAVIOUR UNDER WAVES AND CURRENTS

根据浮式鲆鲽类养殖网箱的结构特点,基于有限元方法对波流共同作用下网箱的运动受力进行数值模拟,并将数值模拟结果与水槽模型实验结果进行比较分析。结果显示:在3种工况条件下,计算机模拟值与实验值吻合较好,验证了程序及数学模型的可靠性。借助于计算机3D可视化技术,可对波流场中网箱结构的运动过程进行虚拟呈现。其中,当流速为26cm/s时,网箱底框架最大倾角可达9°;波浪作用下底框架最大倾角为12°。当波流联合作用时,底框架最大倾角与最大锚绳受力值均高于波浪或水流单独作用时。当水流入射方向与波浪成角度时,底框架最大倾角与锚绳受力随着夹角的增加而减小。今后将通过海上实测进一步对模拟结果进行验证,使数值模拟能够更加精确。

Numerical simulations based on the finite element method(FEM) are conducted to study the behaviour of flatfish cages under currents and waves. The pitch of the bottom frame of the cages and the maximum mooring line force are investigated. A series of tank physical model tests have also been performed to compare and verify the numerical results, and a satisfactory level of agreement has been achieved in the three tested wave and current conditions. Furthermore, the motion of flatfish cages under waves and currents can be visualized. It is found that the maximum pitch of the bottom frame of flatfish cages is 9° with a current speed of 26cm/s, and that under waves is 12°. The maximum pitch and the mooring line force are both greater under combined wave and current effects than when waves and currents are acting individually. When the direction of currents does not agree with that of waves, the maximum pitch decreases as the angel between the incident directions of currents and waves increases. Field measurement will be conducted to further validate the simulation results for improved accuracy of the numerical study.