中国水产科学2025，Vol.32Issue(8)：1174-1185,12.DOI:10.12264/JFSC2025-0051
Nordmøre栅栏的栅条间距和装配倾角对拖网网囊稳定性的影响
Effects of bar spacing and inclination angles of Nordmøre grid on the stability of the trawl cod-end
摘要
Abstract
The Nordmøre grid is an extensive implemented grid bycatch reduction device(BRD)implemented in various shrimp trawl fisheries to reduce bycatch.Variations in the bar spacing and inclination angle of the grid not only affect the hydrodynamic force of the cod-end system but also have a significant impact on the stability.This study employs flume tank model experiments to explore the effects of different bar spacing(15 mm,25 mm,35 mm,and 45 mm)and inclination angles(30°,45°,and 60°)on the drag and shape of the cod-end system.The results showed that:(1)the drag of the cod-end increased as the grid's inclination angle and flow velocity increased but decreased as the bar spacing increased.The average drag of the cod-end in different inclination angles was in the order:A-60°>A-45°>A-30°>without a grid.The drag of the cod-end of the without grid was reduced by 170%,120%,and 72%compared to that at A-60°,A-45°,and A-30°.(2)As the inclination angle of the grid increased,the expansion effect on the contour morphology of the cod-end became significant,with the vertical center point of the cod-end positioned lower.As the flow velocity increased,the overall shape of the cod-end tended to contract.The cod-end circumference with inclination angle of A-60° was increased by 18%and 8%compared to that with inclination angles of A-30° and A-45°.(3)Experimental observations revealed that the drag of the cod-end exhibited a certain degree of fluctuation,becoming more pronounced with increasing flow velocity.At a grid inclination angle of 30°,the drag oscillation effect was the most significant,while at an inclination angle of 45°,the drag oscillation effect of the cod-end was weaker.The average amplitude of the drag oscillation at 30° inclination angle was increased by 26%compared to that at 45°.(4)Bar spacing did not have a significant impact on the fluctuation of drag oscillation.The outcomes of this study hold substantial implications for the optimized design of grid BRDs,which will enhance the selectivity of trawl nets.关键词
栅型兼捕减少装置/栅条间距/倾角/网囊阻力/网囊稳定性Key words
sorting grid/bar spacing/inclination angle/cod-end drag/cod-end stability分类
水产学引用本文复制引用
毛达文,唐浩,张灿,胡夫祥,许柳雄..Nordmøre栅栏的栅条间距和装配倾角对拖网网囊稳定性的影响[J].中国水产科学,2025,32(8):1174-1185,12.基金项目
国家重点研发计划项目(2023YFD2401203) （2023YFD2401203）
国家自然科学基金项目(32373187) （32373187）
上海市自然科学基金项目(23ZR1427000). （23ZR1427000）
