| 摘要 |
PURPOSE:To make smooth flow of fluid around the external face of a tail body of an underwater cruising boat and give a longer inrush distance of the fluid to propelling screws so as to reduce a coefficient of thrust reduction, by shaping the tail body in a form determined by a specific equation of a curve. CONSTITUTION:An underwater cruising boat 1 consists of a round head body BN, a center body BC shaped in a cylindrical form having a certain radius (r) and a tail body BT. Particularly the tail body BT is so framed that the longitudinal section shows a curve determined by a curve equation (X/A)M+(Y/r)N= 1.0(0<M<2.0, 0<N<1.0) and a radius gets shorter towards the stern. Compared with the conventional form shown by a dotted line, this form may provide wider metric area of fluid running to propelling screws 41 51 and increase of flow velocity and a reduction ratio of pressures on the external face can be therefore minimized, providing a lower coefficient of the thrust reduction. |
