- Volume 55 Issue 1
DOI QR Code
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
- Received : 2019.01.28
- Accepted : 2019.02.18
- Published : 2019.02.28
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.
Copper alloy netting;Solidity ratio;Attack angles;Velocity reduction;Hydrodynamic characteristics
- Aarsnes JV, Rui H and Loland G. 1990. Current forces on cage, net deflection, in: Engineering for offshore fish farming. Thomas Telford, London. 137-152. (DOI: 10.1680/ioceefoff.16019.0012)
- Bae JH and An HC. 2014. Measurement of turbulence intensity of cage net using the particle imaging velocimetry. J Korean Soc Fish Ocean Technol 50(4), 595-603. (DOI:10.3796/KSFT.2014.50.4.595) https://doi.org/10.3796/KSFT.2014.50.4.595
- Cha BJ, Kim HY, Bae JY, Yang YS and Kim DH, 2013. Analysis of the hydrodynamic characteristics of chain-link woven copper alloy nets for fish cages. Aquac. Eng 56, 79-85. (DOI:10.1016/j.aquaeng.2013.05.002) https://doi.org/10.1016/j.aquaeng.2013.05.002
- FAO (Food and Agriculture Organization of the United Nations). 2017. Worldwide per capita aquatic consumption, Retrieved from http://www.fao.org/home/en/, Accessed 01 May 2018.
- Fredriksson DW. 2001. Open ocean fish cage and mooring system dynamics. Ph.D. dissertation, University of New Hampshire, NH, U.S.A., 296.
- Harendza A, Visscher J, Gansel L and Pettersen B. 2008. PIV on inclined cylinder shaped fish cages in a current and the resulting flow field, in: 27th International conference on offshore mechanics and arctic engineering. Estoril, Portugal, OMAE, 2008-57748. (DOI:10.1115/omae2008-57748)
- Huang CC, Tang HJ and Liu JY. 2006. Dynamical analysis of net cage structures for marine aquaculture: Numerical simulation and model testing. Aquac Eng 35, 258-270. (DOI:10.1016/j.aquaeng.2006.03.003) https://doi.org/10.1016/j.aquaeng.2006.03.003
- Kim HJ. 2012. Hydrodynamic coefficients of plane nettings according to attack angle, Reynolds number and solidity ratio. Department of Fisheries Physics, Pukyong National University, Korea, 73.
- Kim TH, Kim DA, Ryu CR, Kim JO and Jeong EC. 2000. Flow resistance of model cage net. J. Korean Fish Soc 33(6), 514-519.
- Kim TH, Kim JO and Ryu CR. 2001. Dynamic motions of model fish cage systems under the conditions of waves and current. J Korean Fish Soc 34(1), 43-50.
- Kim TH, Kim CG, Kim HS, Baik CI and Ryu CR. 2002. Hydrodynamic forces on fish cage systems under the action of waves and current. J Korean Soc Fish Ocean Technol 38(3), 190-196. https://doi.org/10.3796/KSFT.2002.38.3.190
- KMI (Korea Maritime Institute), 2003. Per capita aquatic consumption in Korea. Retrieved from https://www.kmi.re.kr/, Accessed 01 May 2018.
- Loland G. 1993. Current forces on, and water flow through and around, floating fish farms. Aquacult Int 1(1), 72-89. (DOI:10.1007/bf00692665) https://doi.org/10.1007/BF00692665
- Lee CW, Kim YB, Lee GH, Choe MY, Lee MK and Koo KY. 2008. Dynamic simulation of a fish cage system and waves. Ocean Eng 35, 1521-1532. (DOI:10.1016/j.oceaneng.2008.06.009) https://doi.org/10.1016/j.oceaneng.2008.06.009
- Moe H, Fredheim A and Hopperstad OS. 2010. Structural analysis of aquaculture net cages in current. J Fluid Struct 26, 503-516. (DOI:10.1016/j.jfluidstructs.2010.01. 007) https://doi.org/10.1016/j.jfluidstructs.2010.01.007
- MOF (Ministry of Oceans and Fisheries), 2018. Per capita aquatic consumption in Korea. Retrieved from http://www.mof.go.kr/article/view, Accessed 01 May 2018.
- Munson BR, Young DF and Okiishi TH. 2008. Fundamentals of Fluid Mechanics. Yoon SH, Kim KS and Kim BH. Wiley, U.S.A., 1-904.
- Tsukrov I, Drach A, DeCew J, Swift MR and Celikkol M. 2011. Characterization of geometry and normal drag coefficients of copper nets. Ocean Eng 38, 1979-1988. (DOI:10.1016/j.oceaneng.2011.09.019) https://doi.org/10.1016/j.oceaneng.2011.09.019
- Zhao YP, Bi CW, Dong GH, Gui FK, Cui Y and Xu TJ, 2013. Numerical simulation of the flow field inside and around gravity cages. Aquac Eng 52, 1-13. (DOI:10.1016/j.aquaeng.2012.06.001) https://doi.org/10.1016/j.aquaeng.2012.06.001