| Drag on Hydroid-Fouled Nets – An Experimental Approach |
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| 引用本文： | Pl LADER,David W. FREDRIKSSON,Jana GUENTHER,Zsolt VOLENT,Nina BLOCHER,David KRISTIANSEN,Lars GANSEL,Jud DECEW.Drag on Hydroid-Fouled Nets – An Experimental Approach[J].中国海洋工程,2015(3):369-389. |
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| 作者姓名： | Pl LADER David W. FREDRIKSSON Jana GUENTHER Zsolt VOLENT Nina BLOCHER David KRISTIANSEN Lars GANSEL Jud DECEW |
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| 作者单位： | SINTEF Fisheries and Aquaculture;United States Naval Academy;University of New Hampshire |
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| 基金项目： | fanatically supported by the Norwegian Research Council through the project Hydroids on aquaculture constructions in Norway(190463/S40);the CREATE Centre for Aquaculture Technology |
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| 摘 要： | The present study investigated the drag increase on aquaculture nets due to biofouling of the colonial hydroid Ectopleura larynx. It had two main parts: firstly the growth characteristics of E. larynx were investigated by use of field tests at a Norwegian aquaculture site; secondly the hydrodynamic drag on the fouled twines was studied in a towing tank by using fabricated models of net twines with artificial hydroid fouling. In the field tests, the growth of the hydroids was first measured after three weeks of immersion and then again after six weeks. During this interval, the density of hydroids and the thickness of the hydroid stem were almost constant(1.4 hydroids/mm and 0.29 mm, respectively), while the average length of the hydroids increased from 6.4 to 11.2 mm. The hydroid length followed a Rayleigh distribution, while the thickness was normal(Gaussian) distributed. Replicas of twines with three different levels of hydroid growth were made(1.5 hydroids/mm twine, hydroid length 9 mm, 16 mm and 20 mm), and the drag on these twines was measured at different towing velocities(0.1 to 1.4 m/s) and with different twine configurations. For the twine with the shortest hydroids(9 mm), the drag was from 1.5 times(Re=4000) to 2.2 times(Re=1000) the drag on a clean twine. For the longest hydroids(21 mm), the drag was 2 times and 3.8 times, respectively.
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| 关 键 词： | hydroid biofouling aquaculture net hydrodynamic drag |
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