不同浸没深度下水平圆柱体的水动力特性试验研究

顺应式的漂浮柔性圆柱型结构物,如深海养殖结构物的浮圈结构、波浪能发电装置的浮体部分等,大多是部分浸没的。目前,学术界和工程界对部分浸没圆柱的水动力特性了解甚少,也使这些新型结构物在设计和分析时面临着一系列的困难。文章利用在拖曳水池中对水平圆柱进行强迫振荡的试验方法,研究了不同浸没深度的水平圆柱体在流、波浪以及波-流耦合作用下的水动力特性,获得了拖曳力系数和附加水质量系数在不同浸没深度下与Reynolds数、KC数和Vr的关系。通过研究发现:(1)在纯流作用下,由于自由液面的存在,超过半浸没的圆柱体的拖曳力系数在超临界范围内将大于全浸没圆柱;(2)在波浪作用下的半浸没圆柱的水动力系数完全不能等同于全浸没圆柱的一半来进行考虑;(3)流的存在对水动力系数的影响比较显著,会导致惯性力系数的增大。

Experimental research about hydrodynamic characteristics of horizontal cylinder under different draft

The floating cylindrical structures, such as the floating frame of the fish farming and the foat-ing bodies of wave energy convertor, are partly submerged. However, few investigations on the character-istics of horizontal cylinder can be found in academic and engineering field presently, which lead to a series of difficulties in the design of such new kinds of structures. Based on the experimental method of forced os-cillation in the towing tank, this paper researches about the effects of Reynolds number, Keulegan-Car-penter number, reduced velocity on the drag coefficients and added mass coefficients of horizontal cylin-der under different draft. The results show that: (1) Due to the influences of free surface, the drag coeffi-cients of cylinder which is more than semi-merged under the current in the supercritical region; (2) An exceedingly difference of the hydrodynamic characters between the fully immerged and semi-submerged condition;(3) The added mass coefficients will increase when existence of current under oscillatory flow.