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论文类型：期刊论文

发表时间：2010-10-01

发表刊物：JOURNAL OF HYDRODYNAMICS

收录刊物：SCIE、Scopus

卷号：22

期号：5

页面范围：926-931

ISSN号：1001-6058

关键字：low-frequency; ISSC; full QTF; Newman's approximation

摘要：For deep water offshore structures, the second order different frequency force may induce large responses in the horizontal directions. The second order different frequency force is usually computed by the Fourier transformation of the second order quadratic transform function (QTF), which is hard to be obtained due to its complexity, time consuming and the influence of 'irregular frequency' in its computation. In practical application Newman's approximation[5] is widely used, without considering its viability.
   Based on a higher-order boundary element method, a numerical model is established for complex solution of second-order diffractions and radiations at different frequencies in bichromatic incident waves. The second-order quadratic transform functions are obtained by the integration of second-order fluid pressure on the body surface. With application of Teng et al's method[9], full QTF's are computed for a typical TLP model ISSC. Computation shows that the second-order quadratic functions have distinct distribution at lower frequency ranges. Comparisons are made on the Newman's approximation with the full difference-frequency QTF.