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Citation:
　Kang Ren and Shili Sun.Free Surface Flow Generated by Submerged Twin-cylinders in Forward Motion Using a Fully Nonlinear Method[J].Journal of Marine Science and Application,2015,(2):146-155.
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Free Surface Flow Generated by Submerged Twin-cylinders in Forward Motion Using a Fully Nonlinear Method

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Title:
Free Surface Flow Generated by Submerged Twin-cylinders in Forward Motion Using a Fully Nonlinear Method
Author(s):
Kang Ren and Shili Sun
Affilations:
Author(s):
Kang Ren1 and Shili Sun2
1. School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Keywords:
free surface flow;  submerged twin cylinders;  fully nonlinear method;  forced steady motion;  boundary element method
分类号:
-
DOI:
-
Abstract:
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.

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Memo

Memo:
Received date: 2014-10-21              Accepted date: 2014-12-10
Foundation item: Supported by the Lloyd’s Register Foundation, the Fundamental Research Funds for the Central Universities (Grant 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).
Corresponding author: Shili Sun          E-mail:shili_sun@163.com
Last Update: 2016-06-23