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论文类型：期刊论文

发表时间：2012-09-01

发表刊物：OCEAN ENGINEERING

收录刊物：SCIE、EI、Scopus

卷号：51

页面范围：129-141

ISSN号：0029-8018

关键字：Submerged sphere; Diffraction; Radiation; Multipoles; Infinite depth

摘要：The wave diffraction and radiation of a submerged sphere in deep water are studied using the multipole method within the frame of linear wave theory. By expressing the velocity potential in spherical harmonics and formulating the problems into truncating and solving M sets of linear equation systems, simple analytical expressions are derived for the hydrodynamic characteristics. A novel analytical expression for the multipoles coefficient is derived to accelerate the numerical implementation. A similar procedure of Wu et al. (1994) and Rahman (2001) is used to condense the expression for the total wave potentials at the sphere surface in the diffraction problem. Results obtained by present model precisely coincide with other numerical schemes, and converge very rapidly with the increase of the truncation parameter that generally the number of series terms N=4 and M=0,1 are sufficient to an accuracy of 3 decimals. A further analysis shows that for large submergences, the surge and the heave exciting forces approach equal. In the mean time, there exists an exact relationship a(11)-0.5=(a(00)-0.5)/2 between the surge and the heave added mass, and b(11)=b(00)/2 between the surge and the heave damping, where j=0 and j=1 correspond to the heave and surge motion, respectively. Extensive numerical results involving convergence of the multipole method, exciting forces and hydrodynamic coefficients for various parameters are also presented. (C) 2012 Elsevier Ltd. All rights reserved.