NUMERICAL SIMULATION OF IRREGULAR WAVE-SIMULATING IRREGULAR WAVE TRAIN  

作　　者：LIANG Xiu-feng YANG Jian-min LI Jun XIAO Long-fei LI Xin 

机构地区：[1]State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200030, China

出　　处：《Journal of Hydrodynamics》2010年第4期537-545,共9页水动力学研究与进展B辑（英文版）

基　　金：supported by the National High Technology Research and Development Program of China (863 Program,Grant No. 2006AA09A107);the National Natural Science Foundation of China (Grant No. 50709079)

摘　　要：In real sea states,damage incidents on offshore floating structures are not due to the whole time series of wave elevation characterized as statistical one but due to few extreme waves or wave groups in irregular wave train.So,using CFD tools to precisely simulate predetermined irregular wave train will lay sound basis for understanding the local characteristic of the flow field and impact loads on offshore floating structures when damage incidents occur.In this article,the generation of single extreme wave is investigated in a numerical wave tank.First,experimental irregular wave train is decomposed into certain number of small-amplitude waves.The Fourier series expansion is performed to determine the amplitude and initial phase angle of each wave component.A hydrodynamic transfer function is used to calculate the amplitude of wave-maker motion associated with each wave component.Then superposition is carried out on all of the wave-maker motion components to get the final wave-maker motion.With the wave-maker motion as input,simulation of the single extreme irregular wave train is modeled successfully.Then the method is applied to simulating a much more complicated irregular wave train.Once again main features of the complicated irregular wave train are reproduced compared with experiment carried out in the new deepwater experimental basin at Shanghai Jiao Tong University.In the simulation,dynamic mesh method is enabled to model the piston-type wave-maker,the Volume Of Fluid（VOF） method is employed to capture the free surface and a dissipation zone is introduced to deal with wave reflection.In real sea states,damage incidents on offshore floating structures are not due to the whole time series of wave elevation characterized as statistical one but due to few extreme waves or wave groups in irregular wave train.So,using CFD tools to precisely simulate predetermined irregular wave train will lay sound basis for understanding the local characteristic of the flow field and impact loads on offshore floating structures when damage incidents occur.In this article,the generation of single extreme wave is investigated in a numerical wave tank.First,experimental irregular wave train is decomposed into certain number of small-amplitude waves.The Fourier series expansion is performed to determine the amplitude and initial phase angle of each wave component.A hydrodynamic transfer function is used to calculate the amplitude of wave-maker motion associated with each wave component.Then superposition is carried out on all of the wave-maker motion components to get the final wave-maker motion.With the wave-maker motion as input,simulation of the single extreme irregular wave train is modeled successfully.Then the method is applied to simulating a much more complicated irregular wave train.Once again main features of the complicated irregular wave train are reproduced compared with experiment carried out in the new deepwater experimental basin at Shanghai Jiao Tong University.In the simulation,dynamic mesh method is enabled to model the piston-type wave-maker,the Volume Of Fluid（VOF） method is employed to capture the free surface and a dissipation zone is introduced to deal with wave reflection.

关 键 词：numerical wave tank irregular wave train Volume of Fluid （VOF） dynamic mesh 

分 类 号：O353.2[理学—流体力学] TU473.16[理学—力学]