Identifying the turbulent flow developing inside and around the bottom trawl by Electromagnetic Current Velocity Meter approach in the flume tank
Identifying the turbulent flow developing inside and around the bottom trawl by Electromagnetic Current Velocity Meter approach in the flume tank
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通过水槽中的电磁流速度计方法识别底拖网内部和周围形成的湍流
DOI：
10.1007/s42241-021-0058-0
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发表时间：
2021-06
影响因子：
2.5
通讯作者：
ong
中科院分区：
文献类型：
--
作者：
Thierry Nyatchouba Nsangue Bruno;Tang Hao;Xu Liu-xiong;Hu Fuxiang;You Xinxing;David Micah Adekunle;Achille Njomoue P;ong
底拖网内部和周围湍流发展的知识不仅对于改善渔具的水动力性能，而且对于通过鱼类响应（例如，群集响应或逃逸行为）的选择性都是非常重要的。利用三维电磁流速仪（ECVM）测量了底拖网网体内部和网体周围的湍流强度和流速比，研究了湍流对底拖网网体性能的影响。应用本征正交分解（POD）方法，从每个可用的ECVM瞬时速度中提取湍流的相平均平均速度场。结果表明，底拖网内存在湍流流动，包括湍流边界层流动和拖网尾流产生的湍流。增加输入流向速度的结果在更快的拖网运动和显着的湍流。拖网翼、方形部分、第一腹、第二腹、第三腹、网囊内部和周围的最大湍流强度分别为0.95%、1.34%、3.40%、4.10%、4.25%和3.80%。结果表明，在拖网网囊内和网囊周围的湍流中，平均速度场恢复为输入流向速度的77.58%。在底拖网中，网翼内、网翼周围、方形部分、第一腹、第二腹、第三腹的平均网宽分别比网翼内、方形部分、第一腹、第二腹、第三腹减少12.92%、13.07%、11.40%、13.00%、0.45%。湍流特性强烈地依赖于结构振动、输入流向速度和网状结构的孔隙度。有必要考虑拖网内部和周围不同部分的速度降低，以改善整个拖曳力的确定、网囊设计和渔具的进一步选择性控制。
The Knowledge of turbulent flow developing inside and around the bottom trawl net is of great importance not only for improving the hydrodynamic performance of the gear but also for the selectivity via the fish response, such as the herding response or escape behavior. The 3-D Electromagnetic Current Velocity Meter (ECVM) measurements were performed to investigate the effect of turbulent flow on the bottom trawl net performance and to analyze the turbulence intensity and velocity ratio inside and around different parts of the trawl net. Proper orthogonal decomposition (POD) method was applied in order to extract the phase averaged mean velocity field of turbulent flow from each available ECVM instantaneous velocity. The results demonstrated the existence of turbulence flow, consisting of turbulent boundary layer flow and the turbulence due to the trawl wake developing all inside and around the bottom trawl net. Increasing input streamwise velocity results in faster trawl movement and a significant turbulent flow. The maximum turbulence intensity inside and around trawl wing, square part, first belly, second belly, third belly, cod-end is 0.95 %, 1.34%, 3.40%, 4.10%, 4.25% and 3.80%, respectively. It was found that the mean velocity field in a turbulent flow inside and around trawl net cod-end recovered on the average was ~77.58% of the input streamwise velocity. It is ~12.92%, ~13.07%, ~11.40%, ~13.00% and ~0.45 % less than that inside and around trawl wing, square part, first belly, second belly, and third belly of the bottom trawl net, respectively. The turbulent flow behavior depends strongly on the structure oscillation, input streamwise velocity and, porosity of the net structure. It is necessary to take into account the velocity reduction inside and around a different part of the trawl net to improve the entire drag force determination, cod-end design, and further selectivity control of the fishing gear.
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影响因子：
2.3
作者：
W. Brevis;M. García-Villalba
通讯作者：
W. Brevis;M. García-Villalba
影响因子：
0.8
作者：
SIROVICH, L
通讯作者：
SIROVICH, L
影响因子：
5
作者：
Bouhoubeiny, Elkhadim;Druault, Philippe;Germain, Gregory
通讯作者：
Germain, Gregory
影响因子：
1.9
作者：
Hu, FX;Matuda, K;Tokai, T
通讯作者：
Tokai, T
影响因子：
5
作者：
Kim, Yong-Hae
通讯作者：
Kim, Yong-Hae