Research on Problems of Stern Flow and Propulsive Performance Considering the Interaction between Ship Hull and Propeller

首先对螺旋桨振动压力分布的解析特性进行了研究。对一个五叶螺旋桨的计算和测量结果表明，在均匀流动和co2 <theta>尾流情况下，振荡压力呈正态分布，而在co5<theta>尾流情况下，振荡压力呈异常分布。其次，研究了边界层和尾迹对船舶模型周围自由表面流动的影响。将朗肯源法与自由表面边界条件下考虑粘滞总水头损失的边界流和尾迹积分法相结合，得到了波浪剖面、压力分布和阻力的计算结果与实测结果进行了比较。第三，利用实验槽内的激光多普勒测速仪对模型螺旋桨尾部区域的速度场进行了测量。研究结果表明，在桨道中采用种子播种检测低速回转的必要性，以及在螺旋桨后方安装定子的可行性。接下来，我们利用激光多普勒测速仪测量了均匀流和螺旋桨滑流中方向舵周围的速度场。测量结果清楚地显示了舵与螺旋桨之间的相互作用。最后，采用点阵法计算了螺旋桨和舵的非定常特性，以研究螺旋桨和舵之间的相互作用。舵对螺旋桨的影响为螺旋桨推力和扭矩波动的7[14%]和螺旋桨效率的2[3%]。

At first we carried out the research on analytical characteristics of oscillating pressure distribution avobe a propeller. The calculated and meadured results for a five-bladed propeller have shown the normal distribution of oscillating pressure in cases of a uniform flow and cos2<theta> wake flow but an abnormal distribution in case of co5<theta> wake flow.Secondly we investigated into the influence of boundary layer and wake on free surface flow around a ship model. The Rankine-source method was combined with an integral method for boundary laver and wake under the boundary condition on the free surface considering the total head loss due to viscosity, The computed results as for wave profiles, pressure distributions and resistances were shown in comparison with measurements.Thirdly we performed measurement of the velocity field in the rear region of a model propeller using the laser-doppler velocimeter in the experimental tank. The results made clear the necessity of seeding to detect the slow turning velocity in propeller race and the availability of stators installed just behina the propeller. As the next step we carried out measurement of the velocity fields around the rudder in the uniform flow and in the slip-stream of the propeller using the laser-doppler velocimeter. The measured results showed clearly the interaction between the rudder and the propeller.Finally the unsteady characteristics of the propeller and the rudder were calculated using the voxted lattice method in order to investigate the interaction between the propeller and the rudder. The effects of the rudder on the propeller were found as 7[14% fluctuations of thrust and torque of the propeller and as 2[3% up of the propeller efficiency.