Wind and Structures

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Numerical investigations on the along-wind response of a vibrating fence under wind action

  • Fang, Fuh-Min (Department of Civil Engineering, National Chung-Hsing University) ;
  • Ueng, Jin-Min (Department of Civil Engineering, National Chung-Hsing University) ;
  • Chen, J.C. (Department of Civil Engineering, National Chung-Hsing University)
  • Published : 2002.04.25
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Abstract

The along-wind response of a surface-mounted elastic fence under the action of wind was investigated numerically. In the computations, two sets of equations, one for the simulation of the unsteady turbulent flow and the other for the calculation of the dynamic motion of the fence, were solved alternatively. The resulting time-series tip response of the fence as well as the flow fields were analyzed to examine the dynamic behaviors of the two. Results show that the flow is unsteady and is dominated by two frequencies: one relates to the shear layer vortices and the other one is subject to vortex shedding. The resulting unsteady wind load causes the fence to vibrate. The tip deflection of the fence is periodic and is symmetric to an equilibrium position, corresponding to the average load. Although the along-wind aerodynamic effect is not significant, the fluctuating quantities of the tip deflection, velocity and acceleration are enhanced as the fundamental frequency of the fence is near the vortex or shedding frequency of the flow due to the occurrence of resonance. In addition, when the fence is relatively soft, higher mode response can be excited, leading to significant increases of the variations of the tip velocity and acceleration.

Keywords

References

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