Optimization off ishing operation for Danish seine gears by numerical analysis of fishing gear dynamics

在这项研究中，发展了一种数值模拟方法，丹麦围网渔具的结构和张力分布在捕捞作业。在实际试验中，测量了围网船的运行参数如围网的航迹、经向长度、拖曳速度等，以及网口深度、围网与网的距离等齿轮运动参数。根据测量的作业参数，对丹麦围网网具的网形和张力分布进行了数值模拟，并与实测值和计算值进行了比较。在捕捞作业中，围网的垂直和水平行为的测量和计算之间有很好的一致性，证明了我们方法的有效性。此外，还提出了用绞线载荷和拖曳速度评估围网渔船绞车机械功的方法，以及用从海底接收的渔具摩擦力评估对海底物理影响的方法。在两个不同拖曳周期和相同拖曳距离的试验中，比较了绞车在海底触网时的计算机械功和对海底的物理冲击。绞车短牵引期的机械功高于长牵引期的机械功。然而，短期对底部的物理影响低于长期。

In this study a numerical simulation method of configuration and tension distribution for Danish seine gears during fishing operation was developed. Operation parameter such as tracks of a seine boat, warp lengths, and hauling speeds and gear movement parameter such as depths of the net mouth and distance between the seine boat and the net were measured in the actual experiments. The net configuration and tension distribution of the Danish seine gear were simulated by numerical simulations based on the measured operation parameter, and then the measured and the calculated parameters were compared. Very good agreement was observed between the measurements and the calculations of the vertical and horizontal behaviour of the seine net during fishing operations, demonstrating the validity of our method. In addition, methods of evaluating the mechanical work of the winches on the seine boat using loads of the warps and the hauling speed and of evaluating the physical impact to the sea bottom using friction force of the gear received from the sea bottom were developed. In two experiments of different hauling period and same towing distance when the net touched it at the sea bottom, the calculated mechanical works of the winches and physical impact to the sea bottom were compared. The mechanical work in the case of short hauling period of the winch was higher than that in the case of long hauling period. However, the physical impact to the bottom in the short period was lower than that in the long period.