大网目底拖网网身长度对网具性能的影响  

Effects of bottom trawl body with lagre-size meshes on net performance

作　　者：王永进[1,2] 万荣[1] 王鲁民[2] 张禹[2] 张勋[2] 

机构地区：[1]中国海洋大学水产学院,山东青岛266003 [2]中国水产科学研究院东海水产研究所,上海200090

出　　处：《海洋渔业》2014年第3期260-264,共5页Marine Fisheries

基　　金：节能型渔具与捕捞装备技术集成研究(201003024);柔性渔具形状与张力数值计算"国家自然科学基金资助(30972286)"

摘　　要：通过拖网模型水池试验,分析比较了我国大网目底拖网网身长度设计参数对网具阻力、网口垂直扩张和能耗系数的影响,并选择网身设计参数的最佳范围.试验结果表明：1）保持大网目底拖网网身前部的网衣结构和尺寸及其他条件不变,网具阻力随身周比（Lb/C）的增加而增大;拖速为2.5 ～3.0 kn时,网具阻力变化幅度较小;2）当Lb/C为0.10 ～0.13时,网具阻力几乎不变,而当Lb/C大于0.13时,网具阻力有较明显的增加,适当缩短网身一定程度上可降低阻力;3）身周比变化对网口垂直扩张有较明显的影响,Lb/C由0.10增加到0.13时,网口高度逐渐增加,之后高度降低,身周比为0.13时网具获得最佳网口垂直扩张;4）身周比在0.10 ～0.13之间时,能耗系数最低;5）在高拖速下网身部位对大网目底拖网性能影响较低速下更明显,且网身网目更易张开.本实验结果对于此规格的底拖网在网身长度的设计中具有一定的指导意义.Trawl net body has important influence on trawl net hydrodynamic performance. When the perimeters of net mouth and net structure of wing sections are fixed, the body structure of trawl net is very important in remaining net stability, leading fish into the codend, and improving trawl net performance when trawling in the water. One large mesh bottom trawl： 1296.00 m × 181.00 m（ 159.60 m）widely used in the East China sea , was selected for study in this paper. Trawl model test in flume tank was conducted to research effects of the ratio of net body length to net mouth perimeter（Lb/C） on the trawl resistance, the height of trawl mouth as well as the coefficient of energy consumption, and to propose the optimum regions of net body design parameters. The experimental results were as follows ： （ 1 ） when the perimeters of net mouth and net structure of wing sections were fixed, the resistance had positive correlation with Lb/C, and had little change in the towing speed of 2.5 -3.0 kn ; （2） when Lb/C was between 0.10 -0.13, the resistance of trawl was the lowest and almost invariant, while Lb/C increased to 0. 13 and more, resistance increased obviously;（3） Lb/C had evident effects on the vertical expansion of net mouth, when Lb/C = 0. 13 the vertical open of net mouth reached the maximum; （4）when Lb/C was 0. 10 -0. 13, the coefficient of energy consumption was the minimum under the present laboratory conditions; （5） the body length of trawl influenced the performance of trawl more in high speed than in low speed, and trawl meshes were easier to open in high speed. The experimental results had some guidance for the design of large-mesh-size bottom trawl used in the East China Sea.

关 键 词：大网目 底拖网 网身 性能 影响 

分 类 号：S972.1[农业科学—捕捞与储运]