Shear layers of a circular cylinder with rotary oscillation
Shear layers of a circular cylinder with rotary oscillation
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DOI：
10.1007/s00348-007-0336-9
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发表时间：
2007-06
影响因子：
2.4
通讯作者：
M. Saad;L. Lee;Tim Lee
中科院分区：
文献类型：
--
作者：
M. Saad;L. Lee;Tim Lee
The behavior of the separated shear layers and the near wake of a circular cylinder with small-amplitude rotary oscillations (Ω1= 0.05−0.15 forff/fo≤ 1.25) were investigated experimentally atRe= 3,700. Measurements of an unforced cylinder were also made for 2,000 ≤Re≤ 10,000 to better understand the effects of rotary oscillations. The results show that the shear-layer vortices formed closer to the cylinder and the distance separating them was found to decrease with cylinder oscillations. The shear-layer frequency, however, increased with increasing forcing frequencyff. The formation-region lengthlfdecreased significantly with increasingffwhile decreased to a lesser extent with increasing normalized oscillation amplitude Ω1. The shear layer also diffused to a lengthLdlarger than that of an unforced cylinder, while thelf-Ld-Strouhal frequency offsetting mechanism was generally maintained. The near wake was of lower momentum compared to an unforced cylinder, and the transverse velocity fluctuations associated with the unforced vortex-shedding frequencyfoalways presented a local peak atff/fo= 0.5, regardless of Ω1tested.
