摘要
基于波浪与海上建筑物作用的高阶边界元方法,以及适应于高阶元计算的消除固角系数与柯西主值积分的边界积分方程,采用大连理工大学自主开发研究的用于计算波浪与海上建筑物相互作用的程序WAFDUTl.4,在势流理论下对单个圆形薄板、单个方形薄板、多个方形薄板,以及带有外嵌板的圆柱体的激振力、水动力系数进行了计算分析。
根据基本控制方程和边界条件,利用满足自由水面波浪条件的格林函数得出边界积分方程,采用高阶元离散求解。对于薄板问题中源点与场点距离很近的情况,采用适用于准奇异积分的自适应高斯积分法进行处理。
文章首先对单个圆形薄板及方形薄板在不同频率、淹没深度、水深下的激振力及水动力系数作了数值计算。以此为基础,接着对Spar平台多个薄板组的水动力系数做了分析,并与Prislin等人的实验结果进行对比,得出无论是多个板还是单个板,实验中的粘性附加质量是势流理论下附加质量的1.1倍左右。最后,本文研究了带有外嵌板的圆柱在波浪作用下的激振力及水动力系数,发现外嵌板的存在增大了垂荡方向的附加质量,减小了圆柱的垂荡运动,为提出新型海工结构物的可行性奠定了基础。
Based on the potential flow theory, WAFDUT1.4, a program developed by Dalian University of Technology, was used to study the exciting force and hydrodynamic coefficients of a single circular and square plate, multiple square plates and a cylinder with nested plates.
The program is based on a higher-order boundary element method (BEM), and a self-adaptive Gaussian integration method was adopted for the evaluation of nearly singular integrals in elements.
The numerical experiment was carried out and the exciting force and hydrodynamic coefficients of a single circular plate, a single square plate, multiple square plates of the Spar platform and a cylinder with nested heave-plates in different cases were analyzed. For the multiple square plates, the comparisons between numerical results and experimental results of Prislin etc al show that added mass of heave plates in real fluid is about1.1times of that in potential assumption. For the cylinder with nested heave-plates, those heave-plates increase the total vertical added mass and thus decrease the heave motion. This can be a good reference for some new offshore structures in the future.
引文
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