Measurement and Analysis of Surface Force and Cavitation of Actual Ship Equipped with CPP

利用科比商船大学的一艘训练船--排水量为762吨、两舷间长度为45米的实船“海丸”，对螺旋桨正上方船体表面的压力波动和螺旋桨空泡现象进行了测量和分析。1.在船体外靠近螺旋桨处安装了与螺旋桨转速同步的频闪仪和摄像机。在夜间和纪伊海峡的清水区进行了试验航行，并成功地记录了空泡现象。2还成功地获得了各种螺旋桨转速和叶片角度条件下的压力脉动数据。到目前为止，关于实际船舶配备CPP的数据报道很少。因此，这里获得的数据可以被认为非常有价值。3压力波动很大 关于我们 在振幅和频率上都受到空化的影响。在频率方面，未发生空化时，主成分为叶片频率，而发生空化并发生辉光时，叶片频率的第二、三阶模态成为主导成分。4由于是转速和叶片角度两个变量，CPP船对空化特性的影响不像FPP船那么简单。分析可能发现，叶片攻角可能是一个可能的变量，能够统一上述两个变量的影响。5到目前为止，已经有几种方法估计螺旋桨表面力，考虑到空泡效应。其中三个人检查了他们的有效性。结果表明，这些常规方法对FPP船是有效的，但在一定程度上是有限的。然而，对于CPP和/或侧斜螺旋桨，这些方法都是不正确的。发展新的估计方法，不仅适用于FPP，而且适用于CPP和侧斜螺旋桨将是未来的任务。少

Measurements and Analysis were carried out regarding pressure fluctuation on hull surface just above a propeller and propeller cavitation phenomena by the use of a actual ship "Fukae-marul", which is a training ship of Kobe University of Mercantile Marine, and has the displacement 762tonnes, the length between perpendiculars 45m, and a 4-bladed skewed and controllable pitch propeller with diameter 2.1m.1 A stroboscope synchronized with propeller revolution and a video camera were mounted on the outside hull near propeller. Experimental voyages were carried out in nighttime and in clear water area of the Kii Channel, and succeeded in recording cavitation phenomena.2 The data of pressure fluctuation were also successfully obtained at various conditions of propeller revolution and blade angle. There have been reported so far a very little data regarding actual ship equipped with a CPP. The data obtained here, therefore, can be considered to be-very valuable.3 Pressure fluctuation is great … More ly influenced by cavitation in both of amplitude and frequency. As for frequency, main component is equal to blade frequency when cavitation does not occur, while the 2nd and 3rd modes of blade frequncy become dominant components as cavitation occurs and glows.4 Because of being two variables of revolution and blade angle, the influence of CPPship on cavitation characteristics is not so simple as that of FPP-ship. The analysis could have found that blade attack angle could be a possible variable to be able to unify the influences of both variables mentioned above.5 There have been so far several methods which estimate the propeller surface force taking into consideration of cavitation effects. Three of them examined about their validities. It was revealed that these conventional methods are valid, though ia a limited extent, for FPP-ship. For CPP and/or skewed propeller, however, all of them are not valid.It would be a future task to develop new estimation method being adaptable not only for FPP but also for CPP and skewed propeller. Less