Free Surface Flow Generated by Submerged Twin-cylinders in Forward Motion Using a Fully Nonlinear Method

作     者：Kang Ren Shili Sun 

作者机构：School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China College of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China 

出 版 物：《Journal of Marine Science and Application》 (船舶与海洋工程学报（英文版）)

年 卷 期：2015年第14卷第2期

页      面：146-155页

核心收录：

学科分类：080704[工学-流体机械及工程] 08[工学] 0807[工学-动力工程及工程热物理] 0813[工学-建筑学] 081301[工学-建筑历史与理论] 

基　　金：Foundation item: Supported by the Lloyd's Register Foundation  the Fundamental Research Funds for the Central Universities (Gram No. HEUCF140115)  the National Natural Science Foundation of China (11102048  11302057)  the Research Funds for State Key Laboratory of Ocean Engineering in Shanghai Jiao Tong University (Grant No. 1310)  and the Specialized Research Fund for the Doctoral Program of Higher Education of China (20132304120028) 

主　　题：free surface flow submerged twin cylinders fullynonlinear method forced steady motion boundary element method 

摘      要：The free surface flow generated by twin-cylinders in forced motion submerged beneath the free surface is studied based on the boundary element method. Two relative locations, namely, horizontal and vertical, are examined for the twin cylinders. In both cases, the twin cylinders are starting from rest and ultimately moving with the same constant speed through an accelerating process. Assuming that the fluid is inviscid and incompressible and the flow to be irrotational, the integral Laplace equation can be discretized based on the boundary element method. Fully-nonlinear boundary conditions are satisfied on the unknown free surface and the moving body surface. The free surface is traced by a Lagrangian technique. Regriding and remeshing are applied, which is crucial to quality of the numerical results. Single circular cylinder and elliptical cylinder are calculated by linear method and fully nonlinear method for accuracy checking and then fully nonlinear method is conducted on the twin cylinder cases, respectively. The generated wave elevation and the resultant force are analysed to discuss the influence of the gap between the two cylinders as well as the water depth. It is found that no matter the kind of distribution, when the moving cylinders are close to each other, they suffer hydrodynamic force with large absolute value in the direction of motion. The trend of force varying with the increase of gap can be clearly seen from numerical analysis. The vertically distributed twin cylinders seem to attract with each other while the horizontally distributed twin cylinders are opposite when they are close to each other.