17级台风工况下玄武岩纤维大型海洋网箱的水动力特性研究

Hydrodynamic Characteristics of a Basalt Fiber Large-scale Marine Net Cage Under Typhoon Conditions of Level 17

网箱浮架是我国深水养殖的重要设施装备,其水动力特性直接关系其工作稳定性。文章针对3层桁架式海洋网箱浮架建立有限元模型,采用流固耦合方法对17级台风正面来流条件下的网箱浮架水动力特性展开模拟计算,并对比分析有无网衣时网箱浮架水动力特性的变化规律。结果表明:在台风正面来流的情况下,网箱浮架的饵料舱侧向支撑点、上层步道板连接管迎浪侧和中层承力结构交叉点是应力集中的主要区域;当浮架悬挂网衣结构时,其垂荡距离减小,但纵摇程度加剧,即网衣结构有利于浮架结构在垂直方向上的稳定,但增加其纵摇运动强度;当悬挂网衣结构时,由于浮架在垂直方向上更为稳定,其饵料舱侧向支撑点、上层步道板连接管迎浪侧的最大应力分别降低5.1%和3.2%,中层承力结构交叉点的最大应力变化不明显,而迎浪侧中下层连接管的最大应力降低8.7%。

The marine net cage is an essential facility and equipment for deep-water aquaculture in China,and its hydrodynamic characteristics are directly related to its operational stability.This paper established a finite element model for a marine net cage with three-layer and employed a fluid-structure interaction method to simulate the hydrodynamic characteristics of the net cage under the frontal flow conditions of a level 17 typhoon.Furthermore,a comparative analysis of the variation patterns in the hydrodynamic characteristics of the net cage with and without a netting structure was conducted.The results showed that under the frontal flow of the typhoon,the main areas of stress concentration in the net cage were the lateral support points of the bait chamber,the upmost walkway board connecting pipes on the windward side,and the cross-points of the mid-level load-bearing structure.When the net cage was equipped with a netting structure,the pendulum distance decreased,but the yawing motion intensified.In other words,the netting structure contributed to the vertical stability of the net cage but increased its yawing motion intensity.With the inclusion of the netting structure,due to the improved vertical stability of the frame,the maximum stress at the lateral support points of the bait chamber,the upmost walkway board connecting pipes on the windward side,decreased by 5.1%and 3.2%respectively,while the maximum stress at the cross-points of the mid-level load-bearing structure exhibited little change.However,the maximum stress on the windward side of the mid-lower level connecting pipes decreased by 8.7%.