頁籤選單縮合
題 名 | 單拖網漁具物理特性研究=Study on the Physics of Trawl |
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作 者 | 李燦然; | 書刊名 | 中華農學會報 |
卷 期 | 56 民55.12 |
頁 次 | 頁41-50 |
關鍵詞 | 單拖漁網; |
語 文 | 中文(Chinese) |
英文摘要 | There has been no systematic research work studied on the relation between the towing powers of trawlers and the sizes of nets and gear applied to the boats and the shape or resistance of net under operation with various kind of pulling speed. Due to strongly appealed demands from the fisheries industry, I have been engage in study to determine the fundamental requirements in the nets and gear design suitable to the boats in some experiments in order to improve the theoretical studying of physical characteristics of construction and operation of trawling geras adopted by the fishers and add something good to the techniqes and production. In this paper describes the evolution of the bottom trawling gears and then gives some interesting results obtained by experiments and some formulas for instance the relationship between towing speed, opening breath of frontal wings, resistance, developing force of otter board, and opening height of the net are offered as follows: 1. In case of two-seam trawl net, a total resistance offered, can be approximately expressed as formula: R=12.5(D/L)λ2V2 Where, D:diameter of a net twine, L: length of each mesh bar, λ: length of ground rope (㎡), V: towing speed (m/sec) 2. D(m), the distance between the frontal ends of two wing nets, is calculated in the following formula, D=2.A.C. sinθ/2 Where, A: legnth of a warp (length from gallows)(m), B:.ength of a sweep line (m), C: length of the net measured between the frontal end of a wing net and the cod head (m), θ: angles subtanded of a pair of warps. 3. L(kg), a developing force of an otter board, is obtained as follows: L= C/2ρSV2 Where, C: developing coefficient 0.79 for upright type otter and 0.77 for ordinary type otter, ρ: density of sea water (105 kg sec2/m?), S: area of an otter board (m2), V: towing spead (m/ sec). 4. Opening height of the net body of two seam net, cana approximately for expressed as: h=0.111a- 2.67V Where, a: the maximum breath of the net body without shrinkage(m). |
本系統中英文摘要資訊取自各篇刊載內容。