低雷诺数条件下并列三圆柱绕流的尾流模式和水动力系数研究
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摘要
该文应用浸入边界法对雷诺数Re(28)100和间距比T/D(28)1.1-5.0条件下的等间距并列三圆柱绕流进行了数值模拟。研究发现,尾流模式与无量纲圆柱间距比T/D密切相关,在所研究的间距比范围内共出现六种尾流模式,分别为:单体尾流模式(T/D(28)1.1-1.2)、偏斜尾流模式(T/D(28)1.3)、第一类Flip-Flopping(FF1)尾流模式(T/D(28)1.4-1.5)、第二类Flip-Flopping(FF2)尾流模式(T/D(28)1.7-2.3)、同步尾流模式(T/D(28)2.5-3.2)和调制尾流模式(T/D(28)3.3-5.0)。通过分析近尾流的涡量图、升阻力系数时程曲线和不同圆柱所受升力的相位差,详细研究了各个尾流模式的特点和联系。
Flow around three side-by-side circular cylinders with the Reynolds number of 100 was numerically investigated using the immersed boundary method. The normalized center-to-center spacing ratio T/D was from 1.1 to 5.0. It was found that the near-wake patterns highly depended on the normalized spacing ratio. With the increasing T/D, six near-wake patterns were observed, i.e., the single-bluff-body pattern(T/D(28)1.1-1.2), biased gap-flow pattern(T/D(28)1.3), the first flip-flopping(FF1) pattern(T/D(28)1.4-1.5), the second flip-flopping(FF2) pattern(T/D(28)1.7-2.3), the synchronized pattern(T/D(28)2.5-3.2) and the modulated pattern(T/D(28)3.3-5.0). The vorticity contours in the near-wake region, the time histories of drag and lift coefficients and the phase differences between lift forces acting on different cylinders were presented. Finally, the characteristics and relations between these near-wake patterns were discussed.
Flow around three side-by-side circular cylinders with the Reynolds number of 100 was numerically investigated using the immersed boundary method. The normalized center-to-center spacing ratio T/D was from 1.1 to 5.0. It was found that the near-wake patterns highly depended on the normalized spacing ratio. With the increasing T/D, six near-wake patterns were observed, i.e., the single-bluff-body pattern(T/D(28)1.1-1.2), biased gap-flow pattern(T/D(28)1.3), the first flip-flopping(FF1) pattern(T/D(28)1.4-1.5), the second flip-flopping(FF2) pattern(T/D(28)1.7-2.3), the synchronized pattern(T/D(28)2.5-3.2) and the modulated pattern(T/D(28)3.3-5.0). The vorticity contours in the near-wake region, the time histories of drag and lift coefficients and the phase differences between lift forces acting on different cylinders were presented. Finally, the characteristics and relations between these near-wake patterns were discussed.
引文
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[2]HAN Z,ZHOU D,TU J H.Laminar flow patterns around three side-by-side arranged circular cylinders using semi-implicit Three-Step Taylor-CharacteristicBased-Split(3-TCBS)Algorithm[J].Engineering Applications of Computational Fluid Mechanics,2013,7(1):1-12.
[3]SUMNER D,WONG S S T,PRICE S J,et al.Fluid behavior of side by side circular cylinders in steady cross flow[J].Journal of Fluids and Structures,1999,13:309-338.
[4]ZDRAVKOVICH M M,STONEBANKS K L.Intrinsically nonuniform and metastable flow in and behind tube arrays[J].Journal of Fluids and Structures,1990,4:305-319.
[5]KUMADA M,HIWADA M,ITO M,et al.Wake interference between three circular cylinders arranged sideby-side normal to a flow[J].Transactions of the JSME,1984,50:1699-1707.
[6]WANG X W,ZHANG H J,ZHOU Y,et al.Flow visualization behind three cylinders of equal and unequal spacing[J].Journal of Flow Visualization and Image Processing,2002,9(2-3):139-151.
[7]JI C N,MUNJIZA A,WILLIAMS J J R.A novel iterative direct-forcing immersed boundary method and its finite volume applications[J].Journal of Computational Physics,2012,231(4):1797-1821.
[8]LI Y,ZHANG R,SHOCK R,et al.Prediction of vortex shedding from a circular cylinder using a volumetric Lattice-Boltzmann boundary approach[J].The European Physical Journal Special Topics,2009,171(1):91-97.
[9]POSDZIECH O,GRUNDMANN R.A systematic approach to the numerical calculation of fundamental quantities of the two-dimensional flow over a circular cylinder[J].Journal of Fluids and Structures,2007,23(3):479-499.
[10]MITTAL S.Excitation of shear layer instability in flow past a cylinder at low Reynolds number[J].International Journal for Numerical Methods in Fluids,2005,49(10):1147-1167.
[11]WILLIAMSON C H K.Oblique and parallel modes of vortex shedding in the wake of a circular cylinder at low Reynolds numbers[J].Journal of Fluid Mechanics,1989,206:579-627.