水中に於ける各種嚢網の抵抗について-III

概要

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In order to make acertain the difference of the shapes at the opening of cod ends afect to what extent upon the resistance, the author made some considerations upon the theoretical relalion between the resistance of the pyramid type cod end, RSn/(KS2) and the shape of its opening, a/b (Eq. III-6 and -7). Where R is the total resistance of the cod end, K the resistance of the unite area of the netting fixed perpendicularly to a stream, Sn the total area of Webbing, S the area at the opening and a/b the ratio of the height and the width at the opening. Further, the author made a series of model experiments of four kinds of cod ends of which the value a/b are changed 1.00, 0.68, 0.50 and 0.35. Thus he compared the actually observed values with the theoretical ones and obtained the results shown in Fig. 13. From this figure, it is found that the coincidence of the observed value of the resistance of the net with its theoretical value is satisfactory and its resistance is nearly constant within the limit of practical shape.
公益社団法人日本水産学会の論文