水中に於ける各種嚢網の抵抗について-II

概要

論文の詳細を見る
In order to study how the difference of the area at the opening of a cod end affects on the resistance of the net, the author deduced a theoretical relation between R/(KSn) and x2/S for various pyramid type cod ends of which the area at the opening is changed when another resistance-factores are maintained constant (Eq. II-3). Where R denotes the total resistance of the cod end, K the resistance of the unit area of plane net fixed at right angle to the stream, Sn the total area of webbing, S the area at the opening and x the total length of the cod end. Further, the author made series of experiments on the model net of cod ends of which the area of the opening are 162cm2., 200, 224, 392 and 578, and compared experimental results with the results calculated by the Eq. II-3 and is plotted in Fig. 11, from which the author make sure of the following fact: In regard to the cod ends which are very short as compared with the area at the opening (e.i. 0<x2/S<5), the resistance is affected by the change of the area at the opening (e.i. the resistance decrease to about half of the resistance of the cod end which is zero in x2/S), but in regard to the cod ends which are moderately slender as are used in fractical trawl net (e.i. 5<x2/S<30), the resistance is hardly affected by the change of the area at the opening.
公益社団法人日本水産学会の論文