A Comparison of Experiment and Calculated Wave-Profiles and Wave-Resistances for a Form Having Parabolic Waterlines
A Comparison of Experiment and Calculated Wave-Profiles and Wave-Resistances for a Form Having Parabolic Waterlines
复制标题
具有抛物线水线的形式的实验与计算的波型和波阻的比较
DOI：
--
复制
发表时间：
1934
期刊：
影响因子：
--
通讯作者：
W. Wigley
中科院分区：
文献类型：
--
作者：
W. Wigley
已经发现，可以计算简单的三维形状的波阻，并且已经得到了一些这样的结果，当形状不违反计算所依据的假设时，这些结果总的来说与实际测量结果符合得很好。布恩。但目前波浪剖面的计算仅限于具有无限吃水深度的二维形式。因此，为了这项研究的目的，在威廉弗劳德实验室制作了两个模型，一个是在机械限制下可能的最大吃水深度，具有垂直侧面和平底，另一个具有最大吃水深度和位移，这将允许在所需的速度范围内测量其阻力，但只有一半吃水深度的垂直侧面，然后在垂直截面上倒圆，直到龙骨处的边缘。第一个模型（编号1254）用于测量波形，并与无限吃水模型计算的波形进行比较;第二个模型（编号1302）用于比较测量和计算的阻力。不可能用第一个模型来达到这个目的，因为由于在舱底的尖角周围产生涡流而增加的阻力将使任何摩擦阻力的计算变得毫无意义，而摩擦阻力必须从测得的力中减去才能产生波阻。然而，为了显示两个模型的计算阻力曲线在形状上的相似性，对其波阻进行了计算。图1显示了这些模型的透视图，其表面方程如下所示（分别为方程（1）和（7））。
It has been found possible to calculate the wave-resistance of simple three dimensional forms, and a number of such results have boon obtained which on the whole have shown good agreement with actual measurements when the forms are such as not to violate the assumptions on which the calculations are founded. But the calculation of wave-profiles is at present limited to two dimensional forms having infinite draft. Hence for the purpose of this research two models were made, at the William Froude Laboratory one of the maximum draft possible under mechanical limitations, with vertical sides and a flat bottom, the other having the greatest draft and displacement which would allow of the measurement of its resistance over the desired range of speeds, but with vertical sides for only half its draft and being then rounded oil in vertical section to an edge at the keel. The first model (No. 1254) was used to measure wave-profiles which were compared with those calculated for a model of infinite draft; the second model (No. 1302) was used for the comparison of measured and calculated resistances. It was impossible to use the first model for tins purpose as the added resistance due to eddying round the sharp corners at the bilges would render quite meaningless any calculation of the frictional resistance which must be subtracted from the measured force to bud the wave-resistance. Its wave-resistance was, however, calculated in order to show the similarity in shape between the calculated resistance curves of the two models. Fig. 1 shows perspective sketches of these models and the equations of their surfaces appear below (equations (1) and (7) respectively).