Higher Harmonics Induced by Waves Propagating over A Submerged Obstacle in the Presence of Uniform Current  

作　　者：宁德志 林红星 滕斌 邹青萍 

机构地区：[1]State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology [2]Department of Civil and Environmental Engineering, University of Maine

出　　处：《China Ocean Engineering》2014年第6期725-738,共14页中国海洋工程（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.51179028,51222902,and 51221961);the National Basic Research Program of China(973 Program,Grant No.2011CB013703);the Program for New Century Excellent Talents in University(Grant No.NCET-13-0076);the Fundamental Research Funds for the Central Universities(Grant No.DUT13YQ104)

摘　　要：To investigate higher harmonics induced by a submerged obstacle in the presence of uniform current, a 2D fully nonlinear numerical wave flume（NWF） is developed by use of a time-domain higher-order boundary element method（HOBEM） based on potential flow theory. A four-point method is developed to decompose higher bound and free harmonic waves propagating upstream and downstream around the obstacle. The model predictions are in good agreement with the experimental data for free harmonics induced by a submerged horizontal cylinder in the absence of currents. This serves as a benchmark to reveal the current effects on higher harmonic waves. The peak value of non-dimensional second free harmonic amplitude is shifted upstream for the opposing current relative to that for zero current with the variation of current-free incident wave amplitude, and it is vice versa for the following current. The second-order analysis shows a resonant behavior which is related to the ratio of the cylinder diameter to the second bound mode wavelength over the cylinder. The second-order resonant position slightly downshifted for the opposing current and upshifted for the following current.To investigate higher harmonics induced by a submerged obstacle in the presence of uniform current, a 2D fully nonlinear numerical wave flume（NWF） is developed by use of a time-domain higher-order boundary element method（HOBEM） based on potential flow theory. A four-point method is developed to decompose higher bound and free harmonic waves propagating upstream and downstream around the obstacle. The model predictions are in good agreement with the experimental data for free harmonics induced by a submerged horizontal cylinder in the absence of currents. This serves as a benchmark to reveal the current effects on higher harmonic waves. The peak value of non-dimensional second free harmonic amplitude is shifted upstream for the opposing current relative to that for zero current with the variation of current-free incident wave amplitude, and it is vice versa for the following current. The second-order analysis shows a resonant behavior which is related to the ratio of the cylinder diameter to the second bound mode wavelength over the cylinder. The second-order resonant position slightly downshifted for the opposing current and upshifted for the following current.

关 键 词：higher harmonics wave-current interaction HOBEM free mode 

分 类 号：P731.2[天文地球—海洋科学] P75