Scale-adaptive simulation of flow past wavy cylinders at a subcritical Reynolds number |
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Authors: | Rui Zhao Jing-Lei Xu Chao Yan Jian Yu |
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Institution: | Rui Zhao · Jing-Lei Xu · Chao Yan · Jian Yu School of Aeronautic Science and Technology,Beihang University,100191 Beijing,China |
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Abstract: | The Xu & Yan scale-adaptive simulation (XY-SAS) model is employed to simulate the flows past wavy cylinders at Reynolds number
8 × 103. This approach yields results in good agreement with experimental measurements. The mean flow field and near wake vortex
structure are replicated and compared with that of a corresponding circular cylinder. The effects of wavelength ratios λ/D
m from 3 to 7, together with the amplitude ratios a/D
m of 0.091 and 0.25, are fully investigated. Owing to the wavy configuration, a maximum reduction of Strouhal number and root-meansquare
(r.m.s) fluctuating lift coefficients are up to 50% and 92%, respectively, which means the vortex induced vibration (VIV)
could be effectively alleviated at certain larger values of λ/D
m and a/D
m. Also, the drag coefficients can be reduced by 30%. It is found that the flow field presents contrary patterns with the increase
of λ/D
m. The free shear layer becomes much more stable and rolls up into mature vortex only further downstream when λ/D
m falls in the range of 5–7. The amplitude ratio a/D
m greatly changes the separation line, and subsequently influences the wake structures. |
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Keywords: | Wavy cylinders · Drag reduction · Vortex shedding · Vibration control · SAS |
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