比重1以下の網糸からなる漁具の模型実験法の検討

概要

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In the case of model testing of fishing gears made of the netting twines such as polyethylene and polypropylene, according to TAUTI's law of similarity for model testing, we have to use those netting twines which float in water for making model nets of such fishing gears. The proper netting materials for the model nets, however, are not found among such netting twines. In this paper, two testing methods for using nylon netting twine, instead of the netting twines with specific gravity smaller than unity, were discussde. One of the methods is to distribute evenly a number of small floats over the nylon netting panels of the model net, so that the specific gravity may become smaller than unity. This method showed experimentally to be effective over a relatively wide range of current speed. In the case of rather high speed movable gears such as trawl gears, another method of model testing theoretically showed that the value of speed ratio between the model and full scale could decaded arbitrarily, pro-vided that the apparent weight of webbing in water was negligibly small compared with water re-sistance.
日本水産學會の論文