アンカー落下時の水抵抗に関する模型実験

概要

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In order to find the fluid drag coefficient (C_D) for dropping of an anchor, authors carried out the tank test on five model anchors which are types of JIS-stockless, JIS-stock, AC-14, Danforth and US-navy, and we obtained the results of model test as follows ; (1) The value of these C_D for dropping of anchors varies according to the dropping posture of anchor and are hardly greater than 1.0, and for example, the value of C_D of JIS-stockless is 0.6 in the case of the posture opening flukes and also 0.85 in the case of the posture closing flukes. (2) Each of the drag of JIS-stockless and AC-14 type in the case of the posture opening flukes is more less than that in the case of the posture closing flukes. (3) Terminal velocity for dropping of an actual anchor with chain cable without brake control will be able to estimte more useful by using the value of twice C_D of anchor itself, and a certain degree of approximate on the terminal velocity (U) for dropping of an actual anchor may be obtained by the following formula, as a guide to good practice. Where W_T is an an anchor-weight in ton. [numerical formula]
社団法人日本航海学会の論文
1976-01-20