柱间有相对运动坐底圆柱群的绕射-辐射分析

THE DIFFRACTION-RADIATION BY ARRAYS OF BOTTOM-SEATED CIRCULAR CYLINDERS WITH RELATIVE MOTION AMONG CYLINDERS

圆柱群是深海海工建筑物的主要承力结构。目前对圆柱群进行的水动力分析大多考虑将圆柱群作为一个整体的情况,即柱群中各柱无相对运动;对于柱间有相对运动圆柱群的研究较少。为此,采用精确代数法研究柱间有相对运动坐底直立圆柱群的绕射-辐射问题。首先开展了柱群中各圆柱做给定单独运动的辐射分析;之后在有入射波浪的情况下,分析了各柱有相对运动圆柱群的绕射-辐射问题;进而求得各圆柱上的水动力、振动幅值等量。作为验证,先将退化情况的结果与已有文献进行了对比。进一步的计算结果表明,在某些波数下,分析中是否考虑柱间相对运动对结果影响较大。

The cylinder arrays are main load-carrying structures in offshore engineering. Most analyses on me hydrodynamics of cylinder arrays usually consider the instance that cylinder arrays react to loads as one whole body, namely that there is no relative movements between each cylinder of the arrays. Analysis on arrays of cylinders, among which relative motions occur, is comparatively rare. Therefore, the diffraction-radiation problem of arrays of bottom-seated vertical circular cylinders with relative motions among cylinders is analyzed by an exact algebraic method in this paper. Firstly, the radiation problem of cylinder arrays among which each cylinder moves with prscribed independent amplitude is studied. Then the diffraction-radiation problem of cylinder arrays with relative movement in the presence of incident waves is analyzed. In addition, the dydrodynamic forces on the cylinders and oscillation amplitudes of each cylinder are obtained. As a validation, the degenerate case is calculated and compared with the pulished one. And further calculations indicate that the influences of the relative movements among cylinders on the hydrodynamic responses are obvious in some range of wave numbers.