Numerical Studies of a Freely Vibrating Cylinder in a Cross-Flow

So, R. M. C.; Liu, Yang; Chan, Suk-Tak; Lam, Ka Se

doi:10.1006/jfls.2000.0377

Cited by 27 publications

(27 citation statements)

References 24 publications

(50 reference statements)

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“…Details of the ARMA technique can be found in Mignolet & Red-Horse (1994). The use of this technique to analyse time series derived from #ow-induced vibration problems has been attempted (Jadic et al 1998;Zhou et al 1999;So et al 2001) before and the results have been compared with those obtained from the Fast Fourier transform method. The technique was found to be quite suitable for #ow-induced vibration problems (Jadic et al 1998).…”

Section: Discussionmentioning

confidence: 99%

“…In the following, the solution of the #ow is described "rst, then the structural dynamics model, the resolution of the #uid}structure interactions and their feedback to the #ow and structural dynamics solutions, and "nally a discussion of the data analysis technique used. These techniques have been discussed in detail in So et al (2001). However, for the sake of completeness, a brief description of these components is also given here.…”

Section: Numerical Methods and Data Analysismentioning

confidence: 99%

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Numerical Studies of Two Side-by-Side Elastic Cylinders in a Cross-Flow

Liu

Lau

Zhou

2001

Journal of Fluids and Structures

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Section: Discussionmentioning

confidence: 99%

Section: Numerical Methods and Data Analysismentioning

confidence: 99%

Numerical Studies of Two Side-by-Side Elastic Cylinders in a Cross-Flow

Liu

Lau

Zhou

2001

Journal of Fluids and Structures

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“…Therefore, it is motion dependent and is much more difficult to estimate. Using an auto-regressive moving average (ARMA) analysis technique, Zhou, So & Mignolet (2000b) and So et al (2001) deduced the effective and fluid damping ratios from the calculated lift and displacement signals of a single cylinder in a cross-flow over a range of Re. In these studies, the cylinder motion was modelled by a twodegree-of-freedom system.…”

Section: Introductionmentioning

confidence: 99%

Free vibrations of two side-by-side cylinders in a cross-flow

et al. 2001

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Free vibrations of two side-by-side cylinders with fixed support (no rotation and displacement) at both ends placed in a cross-flow were experimentally investigated. Two fibre-optic Bragg grating sensors were used to measure the dynamic strain, while a hot wire and flow visualization were employed to examine the flow field around the cylinders. Three T /d ratios, 3.00, 1.70 and 1.13, were investigated, where T is the centre-to-centre cylinder spacing and d is the diameter; they give rise to three different flow regimes. The investigation throws new light on the shed vortices and their evolution. A new interpretation is proposed for the two different dominant frequencies, which are associated with the narrow and the wide wake when the gap between the cylinders is between 1.5 and 2.0 as reported in the literature. The structural vibration behaviour is closely linked to the flow characteristics. At T /d = 3.00, the cross-flow root-mean-square strain distribution shows a very prominent peak at the reduced velocity U r ≈ 26 when the vortex shedding frequency f s , coincides with the third-mode natural frequency of the combined fluid-cylinder system. When T /d < 3.00, this peak is not evident and the vibration is suppressed because of the weakening strength of the vortices. The characteristics of the system modal damping ratios, including both structural and fluid damping, and natural frequencies are also investigated. It is found that both parameters depend on T /d. Furthermore, they vary slowly with U r , except near resonance where a sharp variation occurs. The sharp variation in the natural frequencies of the combined system is dictated by the vortex shedding frequency, in contrast with the lock-in phenomenon, where the forced vibration of a structure modifies the vortex shedding frequency. This behaviour of the system natural frequencies persists even in the case of the single cylinder and does not seem to depend on the interference between cylinders. A linear analysis of an isolated cylinder in a cross-flow has been carried out. The linear model prediction is qualitatively consistent with the experimental observation of the system damping ratios and natural frequencies, thus providing valuable insight into the physics of fluid-structure interactions.

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“…This suggests that a laminar formulation to the #ow-induced vibration problem in this Re range could be appropriate as long as the induced force is Strouhal excitation and its major frequency is identical to the vortex shedding frequency. So et al [20] used these arguments to justify the two-dimensional laminar approach for long slender cylinders with Re(5000. Good agreement with experimental data has been obtained for rigid and elastic cylinders in a cross #ow.…”

Section: Introductionmentioning

confidence: 96%

“…The 2-d.o.f. model was also used by So et al [20] to simulate vortex-induced vibration of a cylinder at sub-critical Re. Instead of the vortex dynamics method, a "nite element technique was used to solve the two-dimensional Navier}Stokes equation governing the #ow "eld.…”

Section: Introductionmentioning

confidence: 99%