Shuchuang Dong

In Japan, the marine aquaculture net cage has an important role in farming pacific bluefin tuna farming in oceans, and the design of the net cage needs to ensure robustness against hostile oceanic conditions. Accordingly, this study focuses on the drag forces and the cage volume of the net cage, and on their variations induced by different design parameters (netting solidity ratio, netting height, and bottom weight). A series of parametric studies on drag force and deformation of the net cage wa

養殖生簀に使われているポリエチレン（PE）製の菱目と角目網地および金網を用いて水槽実験で流れに平行と直角な場合の抗力，および流れに傾けたときの PE 菱目網地と金網の抵抗を計測した。流れに平行な網地の抗力係数は PE 菱目網地，角目網地，金網の順に大きくなることと流れに直角な網地の抗力係数は PE 網地に比べて金網で 0.8-0.9 倍になることが確かめられた。さらに，PE 菱目網地および金網の抗力係数と揚力係数はレイノルズ数，網目係数と迎角の関数で表わすことができ，現場の生簀の挙動を予測するために利用できる。

The labor-intensive catch-hauling method in set-net fisheries faces problems of lower productivity, lower efficiency, and higher operational risk due to aging problem and labor insufficiency. To solve such problems, a novel catch-hauling device using the flexible fire hose and net (hose net), which is placed in the box chamber, was proposed in this study. The hoses were inflated with air injected into one edge of the hose net, and the buoyancy force increased: the net gradually floated up, corne

Abstract The interaction between fluid and fish cage with stocked fish is extremely complex, including fluid and structure, as well as fluid and fish swimming behavior. The on-current swimming pattern of fish schools was found toward the incoming flow in the previous laboratory studies, which is different from the circular swimming pattern commonly observed in the farming site. In this study, a pseudo fish school structure model (PFS) was proposed to reproduce the five circular swimming patterns

Abstract A floating closed fish cage is required for environmental issues such as SDGs (Sustainable Development Goals). The flexible membrane fish cage generally exhibits a reduced motion response. However, the sloshing-induced fluctuations in the internal water remain unclear, despite their critical importance for fish welfare and waste and bait removal in closed fish cages. In the present study, we investigated the water flow velocity, water surface level changes, and fish school behavior in a

Abstract In this study, we numerically investigated the drag force and deformation characteristics of a closed flexible membrane fish cage subjected to uniform flow. The target fish cage is circular, representing a real cage with dimensions of 25 m in diameter, a sheet height of 12.5 m, and a freeboard of 2.5 m. A 1/50 scale model was employed for numerical simulations. The numerical result was validated against experimental data from previous studies. Simulations were conducted at flow velociti

Abstract In the present study, three flexible net cage groups (a single net cage, two net cages arrayed in one column, and three net cages arrayed in one column) were investigated in a flume tank, in order to analyze the hydrodynamic characteristics of the flow and linked flexible net cage, such as the drag force, cage deformation, and flow field inside and around. Based on these results, the fluid-structure interactions of the flexible net cage were discussed. The drag forces and cage deformati