논문 상세보기
pp.341-348
The purpose of this study is to identify the flow resistance characteristics of the trawl net according to the towing speed of the vessel using two trawl nets designed and manufactured based on 2,000 HP. The trawl net consists of wings, bag and cod-end part, two types with wall area of 747 m 2 (Sae Dong Baek) and 1,262 m 2 (Dong Baek) with differences in the size of the trawl net. The result of sea experiments are as follows: the flow resistance of trawl net at the flow velocity = 1 m/s or higher is affected by the difference in the composition of the cod-end rather than the wing or bag part of the Sae Dong Baek´s trawl net, Dong Baek´s the cod-end part has a ratio value of 1.19, compared to Sae Dong Baek´s trawl net with a size of 120 m, and Dong Baek´s trawl net is small at 60 mm. Therefore, the water entering into the net cannot easily pass, which is considered to be a factor that increases resistance at the cod-end part. In the result of the experiment, it was found that decreases exponentially when increases which makes . The constant values when = 1 m/s were 6.72 and 3.75, and values were 1.14 and 0.94, showing a difference between the two nets as the flow velocity increased. The height at the mouth of bottom trawl net decreases exponentially as the current velocity increases; such height given by where the constant and values are 0.85 for the increase in the flow velocity and the value when =1 m/s is 4.35. Therefore, this study investigated the flow resistance characteristics of trawl net at sea. It was possible to obtain more reliable information than previous studies by using a real fishing vessel with advanced underwater measurement devices. As a result, it was possible to analyze the underwater shape change of trawl net and the resulting flow resistance characteristics more quantitatively.
재료 및 방법
해상 실험용 실물 트롤어구의 구성
해상 조업실험용 트롤어구 계측장치
결과 및 고찰
결 론
References
