Numerical Investigation of Vortex-Induced Vibrations of an Elastically-Mounted Circular Cylinder beneath a Free Surface

Document Type : Research Article

Authors

Department of Mechanical Engineering, Iran University of Science & Technology, Tehran, Iran

Abstract

In this paper, a two-dimensional numerical simulation is applied to study the vortex-induced vibrations of an elastically mounted rigid circular cylinder beneath a free surface of fluid. The effect of free surface in laminar flow is investigated with considering two gap-ratios. The natural structural frequency of oscillator is assumed to match the vortex shedding frequency for a stationary cylinder at Re=100. Discretization of flow equations based on the Finite Volume method was implemented in computational fluid dynamics commercial software Ansys Fluent 14.0. User Defined Function hooked in the Software is given to couple the motion of cylinder to flow motion. For simulation of free surface, volume of fluid method is used. The effect of free surface is investigated with using a comparison of transverse displacement diagrams and aerodynamics coefficients diagrams for the two gap-ratios. With approaching cylinder to free surface, results show an abatement in the lock-in region and the amplitude of the oscillations and aerodynamics coefficients are changed depending on the Reynolds location branch.

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References

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Amirkabir Journal of Mechanical Engineering
Volume 50, Issue 4
November and December 2018
Pages 727-740

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