| Numerical Simulation of Self-Excited and Forced Vibration of Circular Cylinders in Current |
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| 作者姓名： | 何长江 段忠东 欧进萍 |
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| 作者单位： | |
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| 摘 要： | Numerical simulations of a low-mass-damping circular cylinder which can oscillate freely at transverse and streamwise directions are presented in this work.The Navier-Stokes equations are solved with finite volume method,and large eddy simulation of vortex is also performed in the calculation.In order to implement dynamic mesh,overlapping grids are generated to lessen the computation for mesh field itself.Self-excited vibrations are firstly calculated to obtain the average amplitudes and frequencies of the target circular cylinder in the current flow situation,and then forced oscillations are implemented with parameters obtained in vortex-induced vibrations previously.With slight amplitude modulation,time series of displacements in vortex-induced vibrations are essentially harmonic.Regarding the fluid force,which are larger in forced oscillations than those in corresponding self-excited cases because the fluid subtracts energy from the forced cylinders.The phase angles between forces and displacements are 0° and 180° for self-excited case and forced case respectively.In vortex-induced vibrations,the interactions between fluid and structure produce some weakly energetic vortices which induce the modulations of amplitude and frequency.
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| 关 键 词： | 振荡圆柱 自激振动 数值模拟 强迫振动 位移时间序列 频率调制技术 电流 Stokes |
Numerical Simulation of Self-Excited and Forced Vibration of Circular Cylinders in Current |
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| Institution: | [1]School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China [2]School of Civil and Hydraulic Engineering, Dulian University of Technology, Dalian 116024, China |
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| Abstract: | Numerical simulations of a low-mass-damping circular cylinder which can oscillate freely at transverse and stream-wise directions are presented in this work. The Navier-Stokes equations are solved with finite volume method, and large eddy simulation of vortex is also performed in the calculation. In order to implement dynamic mesh, overlapping grids are generated to lessen the computation for mesh field itself. Self-excited vibrations are firstly calculated to obtain the average amplitudes and frequencies of the target circular cylinder in the current flow situation, and then forced oscillations are implemented with parameters obtained in vortex-induced vibrations previously. With slight amplitude modulation, time series of displacements in vortex-induced vibrations are essentially harmonic. Regarding the fluid force, which are larger in forced oscillations than those in corresponding self-excited cases because the fluid subtracts energy from the forced cylinders. The phase angles between forces and displacements are 0° and 180° for self-excited case and forced case respectively. In vortex-induced vibrations, the interactions between fluid and structure produce some weakly energetic vortices which induce the modulations of amplitude and frequency. |
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| Keywords: | vortex-induced vibration forced vibration overlapping grid large eddy simulation modulation |
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