Water Surface Wave Radiation Generated by Multiple Cylinders Oscillating With Identical Frequency
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摘要: 在内场中使用简单Green函数的边界元方法与外场的速度势特征函数展开式相结合,用于求解多个同频摇荡剖面引起的水面波辐射问题的频域解.方法适用于外场为定深的水域以及内场的复杂边界条件,各剖面的摇荡模态、幅值和相位可以互不相同.利用摄动展开完整地求解了流场的二阶速度势和各个剖面所受的一、二阶水动力.与单个剖面的情况相比,数值结果证实了多个剖面辐射引起的诸如水波共振和负附加质量等水动力干扰现象,这对于多体结构的锚泊系统和其它海洋工程设施的设计是很重要的.Abstract: The water surface wave radiation problem caused by multiple cylinders oscillating with identical frequency was solved in frequency domain by the boundary element method using simple Green's function in the inner water region combined with the eigenfunction expansions in the outer water region. The numerical method is suitable to the situation of constant depth of outer regions and complicated boundary conditions of inner region, while the oscillating modes, motion amplitudes and phases of the cylinders may be different from one another. The second order potential and hydrodynamic forces acting on ecah cylinder were evaluated completely by perturbation method. Compared with the case of single oscillating cylinder, hydrodynamic interference phenomena, such as wave resonance and negative added mass, of the radiation problem due to the oscillatory motions of multiple cylinders are identified which is of engineering importance to the design of moorings and other facilities involving multiple structures.
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[1] Ursell F.On the heaving motion of a circular cylinder on the surface of a fluid[J].Quart J Mech Appl Math,1949,2(2):218~231. [2] Tasai F.Formula for calculating hydrodynamic force of a cylinder heaving on a free surface[R].Report of Research Institute for Applied Mechaincs,Vol,3,1960. [3] Frank W.Oscillation of cylinders in or below the free surface of deep fluids[R].Naval Ship Research and Development Center,Report No 2375,1967. [4] Andersen P.Ship motion and sea loads in restricted water depth[R].Danish Center for Applied Mathematics and Mechanics,Report No 148,1978. [5] Yeung R W.A singularity-distribution method for free-surface flow problem with an oscillating body[R].University of California,Berkeley,Report No NA 73-6,1973. [6] Nestegard A,Sclavounos P D.A numerical solution of two-dimensional deep water wave-body problems[J].J Ship Research,1984,28(1):48~54. [7] Poul Andersen,He Wuzhou.On the calculation of two-dimensional added mass and damping coefficients by simple Green's function technique[J].Ocean Engineering,1985,12(5):425~451. [8] 贺五洲,戴遗山.有限水深二维辐射问题的二阶速度势和水动力[J].中国造船,1987,(97):1~13. [9] 贺五洲,戴遗山.线元上分布奇点的诱导速度势和诱导速度[J].哈尔滨船舶工程学院学报,1991,12(2):139~147. [10] 谢楠,戚心源,郜焕秋.有限深水中沉井的水动力计算[J].水动力学研究与进展,1992,A7(4):434~443.
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