船の発進実験に就て

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By a model experiment of a ship, the author noticed a fact that there is a special adherent layer of water between the hull and the layer commonly expressed as a displacement thickness. While the latter thickness is expressed by √<ν t_l>, where ν is the coefficient of the kinematic viscosity of water and t_l the time lapsed from the start of acceleration, the adherent layer is dependent on the velocity of the ship. The thrust of ship, or pulling weight F, during an acceleration is expressed as follows: - F=m_0M_α. Where, M=mass of the ship, m_0=1+m_5+m_6, m_5=coefficient of the added water mass due to the total resistance, and m_6=coefficient of the adherent mass. Then, α=F/(1+m_5+m_6) M. During the experiment, F, m_5 and M were kept constant, and the author found that m_6 changes in a special manner depending on V. In an experiment of l.5m model and F=1,000g, m_6 showed its effect when V has increased to 0.5 m/s and m_6=0.061, then it increased with V, and after V=1.389 m/s, m_6=0.087, m_6 remained constant. See Fig.2. After V has reached l.667 m/s, both V and m_6 were seen remaining constant.
社団法人日本船舶海洋工学会の論文
1977-06-30