船体抵抗試験と乱流剥離との関係に就いて

概要

論文の詳細を見る
Dr. M. Yamagata investigated the minimum Reynolds' numbers (Rc) for resistance measurements of various ship forms and found that 1) they vary with ship forms, 2) the tendency of their variation is reverse in the case of discontinuous forms to that of the usual hull forms. We can also find the fact that the smaller the Reynolds' numbers, the greater the specific residuary resistances. These phenomena present themselves in many other experiments, the use of different formula of frictional resistance cannot always erase them out. Are the causes of these facts to be found in the laminar boundary layer itself or in the phenomena of the turbulent layer? The author has investigated this problem and reached to the following conclusions ; 1) In the case of discontinuous forms, the separation of boundary layer is forced to occur in the region of fore body. With the fuller forms, the transition is difficult to take place, the boundary layer may separate in laminar condition for low Reynolds' numbers, while the finer forms come into turbulent state. This condition may explain the trend of Rc curve for Cb. 2) In the case of usual ship forms, the effects of Reynolds' number present themselves as the movement of the turbulent separation point, the position of which moves ahead with the reduction of Reynolds' number as the stern wave front advances.
社団法人日本船舶海洋工学会の論文