Three-dimensional numerical simulation of two-degree-of-freedom VIV of a circular cylinder with varying natural frequency ratios at Re = 500
Wang, Enhao and Xiao, Qing and Incecik, Atilla (2017) Three-dimensional numerical simulation of two-degree-of-freedom VIV of a circular cylinder with varying natural frequency ratios at Re = 500. Journal of Fluids and Structures, 73. pp. 162-182. ISSN 0889-9746
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Abstract
The two-degree-of-freedom (2DOF) vortex-induced vibration (VIV) of a circular cylinder with varying in-line to cross-flow natural frequency ratios (f* = fnx/fny) is studied using a three-dimensional (3D) computational fluid dynamics (CFD) approach. Numerical simulation is carried out for a constant mass ratio of 2 at a fixed Reynolds number Re = 500. The reduced velocity ranges from 2 to 12. Three natural frequency ratios are considered, i.e., f* = 1, 1.5 and 2. The structural damping is set to zero to maximise the response of the cylinder. The main objective of this study is to investigate the effect of f* on the 2DOF VIV responses and the 3D characteristics of the flow. It is discovered that there is a significant increase in the vibration amplitude, and the peak amplitude shifts to a higher reduced velocity when f* increases from 1 to 2. A single-peak cross-flow response is observed for the identical in-line and cross-flow mass ratios when f* = 2. Dual resonance is found to exist over the range of f* studied. The preferable trajectories of the cylinder in the lock-in range are counterclockwise figure-eight orbits. Oblique figure-eight trajectories appear at Vr = 6, 7 and 8 when f* = 1. The third harmonic component which is observed in the lift fluctuation increases with f*. The correlation decreases in the lock-in range and reaches its minimum value around the transition region between the lock-in and post-lock-in ranges. Three vortex shedding modes (2S, P + S and 2P) appear in the present simulation. A dominant P + S mode is associated with the oblique figure-eight trajectories. Variation of vortex shedding flows along the cylinder is observed leading to the poor correlation of the sectional lift forces.
Creators(s): |
Wang, Enhao ![]() ![]() | Item type: | Article |
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ID code: | 60893 |
Keywords: | three-dimensional (3D), computational fluid dynamics (CFD), vortex-induced vibration (VIV), two-degree-of-freedom (2DOF), natural frequency ratio, Naval architecture. Shipbuilding. Marine engineering, Ocean Engineering |
Subjects: | Naval Science > Naval architecture. Shipbuilding. Marine engineering |
Department: | Faculty of Engineering > Naval Architecture, Ocean & Marine Engineering |
Depositing user: | Pure Administrator |
Date deposited: | 09 Jun 2017 13:13 |
Last modified: | 08 Jan 2021 04:13 |
Related URLs: | |
URI: | https://strathprints.strath.ac.uk/id/eprint/60893 |
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