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

Abstract

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%.

Keywords

• basalt fibers
• marine net cage
• hydrodynamic characteristics
• fluid-structure coupling
• numerical simulation