摘要
为了解不同工况条件下的网具形态变化,以南极磷虾捕捞船“龙腾”轮采用的四片式拖网为研究对象,基于修正的田内准则制作1/35的模型网进行循环动水槽试验,考察流速(v)、水平扩张比(L/S)和渔获物对网具(整体形态、阻力和能耗系数)的影响。结果表明:拖网网口形状随流速、L/S的增大呈被“压缩”趋势,当L/S=0.35、v=30 cm/s时,网口形态最佳,网囊中有或无模拟渔获物时的网口形状变化情况相似;流速一定时,网口面积随L/S的增大而增大,L/S一定时,网口面积随流速的增大而减小,在低流速、高水平扩张比条件下,有模拟渔获物时的网口面积随流速、L/S改变而变化的程度较空网时更小;网身随流速、L/S的增大同样呈被“压缩”趋势,且L/S改变时的“压缩”程度较流速更大,有模拟渔获物时的网身末端上扬现象较空网时更明显,且网身长度较空网时明显增长;流速不变时,随L/S的增大,网具阻力增加,能耗系数减小,且二者的变化程度均呈减缓态势;而L/S不变时,随流速的增大,网具阻力和能耗系数均增大,有模拟渔获物时的网具阻力与能耗系数较空网时更大,且流速越大,网具能耗系数与空网时的差异越大。研究表明,当L/S=0.35、v=3.0 kn时,可使网具以较佳作业性能运行。
In order to probe into configuration changes of the trawl configuration gears under different working conditions,the effects of current speed(v),horizontal opening ratio(L/S) and catch on the mouth opening overall shape,drag and energy consumption coefficient were investigated in A 1/35 scale four-pieces krill(Euphausia superba) trawl by the Antarctic krill fishing vessel “Longteng” manufactured based on modified Tauti's law and tested in a flume tank.The tank had the circulating water tank with main dimension of 22.0 m(length)×8.5 m(width)×2.7 m(height),the side observation scale of 9.0 m(length)×2.2 m(width)×1.6 m(standard water depth),and a length of 7.3 m,width 1.5 m viewing window at the tank bottom.The flow rate in the tank was measured by a propeller type flow meter(Tokyo Measurement Technology Co.,Ltd.) for 10-200 cm/s with an accuracy of 2%.The results showed that the shape of net mouth tended to be “compressed” with the increase in v and L/S,with the best shape of mouth at L/S=0.35,and v=30 cm/s,without significant effect of the catch on the shape of mouth.The area of the mouth was found to be increased with the increase in L/S at constant v and decreased with the increase in v at constant L/S.There was less change in the area of mouth with simulated catch than that in the empty with the change in current speed,and L/S under the condition of low velocity and high horizontal opening.The net body shape also tended to be “compressed” with the increase in current speed and L/S and the change in L/S had a greater impact on it,the end of net body with simulated catch rose more obviously than that in empty net and the length of net was also increased obviously than it.The trawl net drag force was increased with the increase in L/S,while the energy consumption coefficient was decreased and the change degree of both showed a slowing down trend,both the trawl net drag force and the energy consumption coefficient were increased with the increase in current speed.There were greater drag force and en
作者
朱美熹
唐浩
刘伟
张锋
孙秋阳
许柳雄
胡夫祥
ZHU Meixi;TANG Hao;LIU Wei;ZHANG Feng;SUN Qiuyang;XU Liuxiong;HU Fuxiang(College of Marine Sciences,Shanghai Ocean University,Shanghai 201306,China;National Engineering Research Center for Pelagic Fishery,Shanghai 201306,China;Key Laboratory of Sustainable Exploitation of Ocean Fisheries Resources,Ministry of Education,Shanghai 201306,China;Tokyo University of Marine Science and Technology,Tokyo 108-8477,Japan)
出处
《大连海洋大学学报》
CAS
CSCD
北大核心
2023年第2期331-339,共9页
Journal of Dalian Ocean University
基金
国家自然科学基金(31902426)
上海市青年科技英才扬帆计划资助(19YF1419800)。
关键词
南极磷虾
拖网
形态
渔获量
水平扩张比
Euphausia superba
trawl
shape
catch
horizontal opening ratio
