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A study on flow velocity reduction and hydrodynamic characteristics of copper alloy netting by solidity ratios and attack angles

구리합금그물감의 공극률 및 영각에 의한 유속 감소와 유체역학적 특성에 관한 연구

KANG, Ahrim;LEE, Jihoon
강아림;이지훈

  • Received : 2019.01.28
  • Accepted : 2019.02.18
  • Published : 2019.02.28

Abstract

Recently, copper alloy netting has been proposed as a material for aquaculture facilities that can be set in harsh offshore environments. To design a cage made of copper alloy netting, it is necessary to calculate the flow of water through the netting and force of external sources on the netting. Therefore, this study measured and analyzed the current velocity reduction after passing through the netting and the hydrodynamic forces acting on the netting using copper alloy netting with nine solidity ratios. As a result of the reduction rate of the flow velocity through the netting, the flow reduction rate was increased as the solidity ratio of netting was increased. The flow reduction rate was also increased as the attack angle on the netting was decreased. In analyzing the resistance on the netting, we also discovered that resistance was increased with increase in the flow velocity and solidity ratio. An analysis of the hydrodynamic coefficient acting on the netting is shown that the drag coefficient tends to increase as the attack angle increases. We also analyzed the hydrodynamic coefficient according to the variation of the Reynolds number. When the drag coefficients acting on the netting were analyzed with the different Reynolds numbers, the Reynolds number increased from over 0.3 m/s to a relative constant. Finally, the copper alloy nettings had a smaller velocity reduction rate when comparing the flow velocity reduction rate between copper alloy nettings and nylon nettings.

Keywords

Copper alloy netting;Solidity ratio;Attack angles;Velocity reduction;Hydrodynamic characteristics