Aerodynamic characteristics and excitation mechanisms of the galloping of an elliptical cylinder in the critical Reynolds number range

Ma, Wenyong; Macdonald, John H G; Liu, Qingkuan

doi:10.1016/j.jweia.2017.10.006

Cited by 8 publications

(5 citation statements)

References 13 publications

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“…The Strouhal number of the circular cylinder used in this study agreed well with the results reported by Fox and West (1993). According to the static wind tunnel tests performed by Ma et al (2017)…”

Section: Strouhal Number (St)supporting

confidence: 89%

Wind Resistance Evaluation of Existing Standing Buddha Statue Using 3D Laser Scanning and CFD

2023

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Underestimating the aerodynamic forces acting on structures can lead to them sustaining severe damage.Currently, there are limited studies on the wind flow around complex-shaped tall structures such as the Buddha statue and the aerodynamic forces acting on them. This study discusses the applicability of 3D terrestrial laser scanning in the 3D modeling of an existing complex-shaped standing Buddha statue. This study also aims to shed light on the wind resistance evaluation for the maintenance of a contemporary standing Buddha statue.Large Eddy Simulation (LES) was utilized to calculate the wind flow around it. The results showed that there was no recirculation region at its top. The horseshoe vortex moved closer to the Buddha statue as the angle of attack (AOA) increased. However, the size of the wake region decreased. Sudden changes in the aerodynamic force coefficients and Strouhal number were observed in the Buddha statue-owing to vortices caused by the cross-sectional variations in shape and a setback. Finally, the most vulnerable parts of the Buddha statue which might require optimal maintenance and renovation are mentioned. Results from this study can be used in developing maintenance techniques for similar complex-shaped structures.

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Section: Strouhal Number (St)supporting

confidence: 89%

Wind Resistance Evaluation of Existing Standing Buddha Statue Using 3D Laser Scanning and CFD

2023

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“…Large amplitude vibrations in the critical Reynolds number range for a smooth elliptical cylinder under normal wind have also been observed in wind tunnel tests (Ma et al, 2017b;Ma et al, 2017c). The results imply that imperfections and axial flow may not be necessary conditions for vibrations in the critical Reynolds number range.…”

Section: Introductionmentioning

confidence: 62%

“…However, the flow regime in which dry galloping occurs and the effect of surface roughness on them remains unclear. From the practical point of view, dry galloping has been observed in wind tunnel tests many times, and they have been reproduced by the author's group for circular cylinders under normal and skew winds (MA et al, 2017a;Ma et al, 2017b;Ma et al, 2017c) . However, these vibrations are rarely observed in the field.…”

Section: Introductionmentioning

confidence: 88%

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The effect of surface roughness on aerodynamic forces and vibrations for a circular cylinder in the critical Reynolds number range

Liu

Macdonald

et al. 2019

Journal of Wind Engineering and Industrial Aerodynamics

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The excitation mechanism of vibrations of circular cylinders in the critical Reynolds number range remains unclear. These vibrations have been observed in wind tunnels many times but rarely in the field. The surface roughness of the cylinder might be a reason for this difference. Aiming to reveal the effect of surface roughness on the aerodynamic forces and vibrations in the critical Reynolds number range, seven circular cylinders with various value of surface roughness were covered with abrasive papers and tested in stationary and elastically mounted wind tunnel tests. The results show that the surface roughness significantly influences the aerodynamic forces in the critical Reynolds number range by reducing the range of transitions on boundary layers. These influences include suppressing the jumps in lift coefficients and other phenomena that relate to a bistable state occurring only for less rough cylinders. Therefore, sufficient surface roughness can mitigate the vibrations in the critical Reynolds number range by suppressing the bistable state in which the vibrations appear.

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“…Some researchers (Bearman et al, 1987;Blevins, 1977Blevins, , 1990Fung, 1955) pay attention to the applicability of the quasi-steady assumption, and they believed that the reduced wind velocity should be higher than 10 (circular cylinders) or 30 (square cylinders). Under some specific circumstances, for example at the critical Reynolds number (Ma et al, 2017a(Ma et al, , 2017b, or for low-speed galloping (Chen et al, 2017(Chen et al, , 2021Gao and Zhu, 2017;Mannini et al, 2014Mannini et al, , 2018, the quasi-steady assumption might be disabled to modeling the galloping vibration. Another method of studying the features of galloping vibration is wind tunnel tests, which can accurately capture the galloping response without worrying about whether the quasi-steady assumption applies.…”

Section: Introductionmentioning

confidence: 99%

Effects of damping and helical fillets on galloping vibration of stay cable installed with a rectangular lamp

Chen

2023

Advances in Structural Engineering

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Lamps attached on the stay cable can change the stable circular cross-section of the stay cable, which is easy to cause galloping vibration. Stay cables of the Kuipu bridge in the Fuzhou City of China were equipped with damper and helical fillets. After the installation of rectangular lamps on this bridge, no obvious vibration of the stay cables was observed. This is totally different from another bridge, the Kuimen bridge in the Chongqing City of China, which has been recently reported by the authors. The purpose of this study is to clarify the effects of the helical fillets and the structural damping on galloping vibration. The features of galloping vibration of the stay cable attached to a rectangular lamp were carefully studied, and the effectiveness of damping and helical fillets in reducing the galloping vibration was evaluated. First, the force measurement wind tunnel tests on the segmental test model were carried out, and the lift and drag coefficients of the stay cable attached to the rectangular lamp were measured. The dangerous wind attack angle of galloping vibration was predicted by the galloping force coefficient. Second, 3-dimensional vibration measurement wind tunnel tests were carried out to measure the wind-induced response of the cable-lamp test models. The variation of wind-induced response of stay cable with yaw angle and wind velocity was measured for test models with and without helical fillets. In the test, the features of wind-induced vibration were studied at the damping level of 0.1%, 0.6%, 0.7%, 0.8%, and 1.0%. According to Den Hartog’s theory, the minimum coefficient of galloping force is about −9.8. The experimental results of 3-dimensional vibration measurement wind tunnel tests show that the helical fillets wrapped on the cable surface can enhance the critical wind velocity to a certain extent, but the critical wind velocity is still far lower than the design wind velocity. When the damping ratio of the stay cable is up to 1.0% ( SC = 35.1), the galloping vibration of the stay cable attached to a rectangular lamp on the Kuipu Bridge can be effectively mitigated.

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Aerodynamic characteristics and excitation mechanisms of the galloping of an elliptical cylinder in the critical Reynolds number range

Cited by 8 publications

References 13 publications

Wind Resistance Evaluation of Existing Standing Buddha Statue Using 3D Laser Scanning and CFD

Wind Resistance Evaluation of Existing Standing Buddha Statue Using 3D Laser Scanning and CFD

The effect of surface roughness on aerodynamic forces and vibrations for a circular cylinder in the critical Reynolds number range

Effects of damping and helical fillets on galloping vibration of stay cable installed with a rectangular lamp

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