| 摘要 |
PURPOSE:To reduce the propulsion resistance of a ship and improve its propelling force by rotatably supporting an impeller near the center below the draft of a bow. CONSTITUTION:An impeller 1 absorbs the momentum of the water stream near the surface of a hull, thereby the flow speed is reduced and the friction resistance is decreased. The effect of the impeller 1 applied to the boundary layer of the rear fluid at the hull surface is shown in a figure. The horizontal axis indicates the flow speed (u) in the boundary layer, and the vertical axis indicates the vertical distance from the hull surface. The right vertical line indicates the advance speed of the ship, and delta indicates the position of the boundary layer thickness when no impeller exists. The solid line shown the case in which an impeller is provided, and the dotted line shown the case in which only a spherical bow exists with blades being removed. Accordingly, the flow speed near the hull surface is reduced by providing the impeller 1 as compared with the case in which no impeller is provided. That is, the friction resistance of the ship is reduced and propulsion performance is improved. |
