# 大雷诺数下串列方柱的PIV试验研究PIV Experimental Investigation of Series Parallel Column with High Reynolds Number

Abstract: In order to study the mechanical structure and the characteristics of the flow field around the building to reduce the loss caused by improper engineering design. Particle Image Velocimetry (PIV) was used, under different working conditions in tandem column. The wind tunnel experiments with Reynolds numbers of 6.8 × 103, 1.4 × 104, 2.2 × 104 and 3.42 × 104 were carried out. The flow field characteristics and St characteristic of unsteady flow around the square column under large Reynolds number are studied. The results demonstrate that under the large Reynolds number, the unsteady flow field characteristics of the downstream square column can be clearly observed in the PIV test. The time-averaged flow field in the distance from the square column 2D and instantaneous flow field in the range of 3.5D from the square column, the interference from the upper side column is larger. In less than 3.5D, when the project should consider the upstream interference, a reasonable structural design. The downstream column St is on the brink of a constant value of 0.12. In fluid machinery and construction design of the structure has important guiding significance.

1. 引言

2. IV试验布置

Figure 1. Arrangement of wind tunnel test-bed

Figure 2. Schematic diagram of the flow around a square column

3. 实验结果及分析

3.1. 下游方柱中间断面的时均流速流动特性分析

(a) Re = 6.8 × 103 (b) Re = 1.4 × 104 (c) Re = 2.2 × 104 (d) Re = 3.42 × 104

Figure 3. Horizontal velocity profile

(a) G = 4.0 (b) G = 6.0

Figure 4. Vertical velocity profile

3.2. 下游方柱绕流瞬时流场分析

Figure 5. Transient flow field under different clearance ratio and Reynolds number

3.3. 下游方柱绕流时均流场分析

Figure 6. Time-averaged flow fields of different Reynolds number and gap ratio downstream

Figure 7. G = 4.0, Time-averaged flow field of the side column under different Reynolds numbers

Figure 8. Relationship between length of confluence under different Reynolds numbers and different clearance ratios

3.4. 瞬时流场与时均流场的比较

3.5. 不同间距比时旋涡脱落StRe的关系

St在圆柱、方柱等钝体绕流研究领域中有着重要的作用，其表达公式为：St = fD/U0 (f表示涡脱落频率)。图9是在几种间隙比的工况下，Re分别为6.8 × 103、1.4 × 104、2.2 × 104、3.42 × 104时的St数。

(a) (b)

Figure 9. The relationship between Reynolds number and St of different clearance ratio

4. 结论

1) 通过PIV风洞试验，观察到大雷诺数下，上游方柱对下游方柱周围非定常流场的干扰特征，时均流场中在距离方柱小于2D时受影响较大，相比单方柱的流场更加剧烈，大于2D则干扰较小。而瞬时流场在小于约3.5D的范围内影响较大。在小于3.5D的条件下，流体机械或者建筑结构工程中不应忽略上游方柱的干扰。

2) G ≤ 4时，下游方柱的水平时均流速随间距的增大而减小；当G > 4时，时均流速特性与单方柱趋于一致。时均流速随着Re的增大也逐渐增大。

3) 方柱下游回流区的长度随间距的增大逐渐增大，随雷诺数的增大而逐渐减小，整体上接近于方柱的特征长度。

4) 小于临界间距时，St随间距增大而缓慢增大；大于临界间距时，St随间距增大而逐渐减小。St随雷诺数增大介于0.11~0.16之间变化，最终接近于常值0.12，相对单方柱的St略小。

NOTES

*通讯作者。

[1] Lyn, D.A., Einav, S., Rodi, W., et al. (1995) A Laser-Doppler Velocimetry Study of Ensemble-Averaged Characteristics of the Turbulent Near Wake of a Square Cylinder. Journal of Fluid Mechanics, 304, 285-319.
https://doi.org/10.1017/S0022112095004435

[2] Durão, D.F.G., Heitor, M.V. and Pereira J.C.F. (1988) Meas-urements of Turbulent and Periodic Flows around a Square Cross-Section Cylinder. Experiments in Fluids, 6, 298-304.
https://doi.org/10.1007/BF00538820

[3] 林纬, 喻九阳, 郑小涛, 聂思皓, 徐成. 脉动流方柱绕流特性研究[J]. 工程热物理学报, 2014(2): 338-341.

[4] 张力, 李金生, 杨仲卿, 丁林. 方柱–弹性分隔板涡致振动数值研究[J]. 工程热物理学报, 2014(4): 687-690.

[5] 刘志文, 吕建国, 刘小兵, 陈政清. 串列双幅断面颤振稳定性气动干扰试验研究[J]. 振动工程学报, 2016(3): 403-409.

[6] Kim, K.C., Lee, M.B., Yoon, S.Y., et al. (2002) Phase Averaged Velocity Field in the Near Wake of a Square Cylinder Obtained By a PIV Method. Journal of Visualization, 5, 29-36.
https://doi.org/10.1007/BF03182600

[7] 施鎏鎏, 余俊, 万津津, 刘应征. 近壁方柱绕流非定常特性的TR-PIV测量[J]. 工程热物理学报, 2009(8): 1312-1314.

[8] Bhattacharyya, S. and Maiti, D.K. (2006) Vortex Shedding Suppression for Laminar Flow Past a Square Cylinder Near a Plane Wall: A Two-Dimensional Analysis. Acta Mechanica, 184, 15-31.
https://doi.org/10.1007/s00707-005-0304-5

[9] 周云龙, 邓冬, 曹茹, 洪文鹏. 气液两相流并列双方柱绕流涡脱特性数值研究[J]. 中国电机工程学报, 2009(17): 88-96.

[10] Sohankar, A. (2012) A Numerical Investigation of the Flow over a Pair of Identical Square Cylinders in a Tandem Arrangement. International Journal for Numerical Methods in Fluids, 70, 1244-1257.
https://doi.org/10.1002/fld.2739

[11] 陈素琴, 黄自萍, 沈剑华, 等．两串列绕流的干扰数值模拟研究[J]. 同济大学学报(自然科学版), 2001, 29(3): 320-325.

[12] 吴二七, 周岱, 付功义. 串列方形钝体构筑物绕流的数值分析[J]. 上海交通大学学报, 2012(1): 130-135+141.

[13] 吕启兵, 杨斌, 杨忠超, 李鹏浩. 串列双方柱绕流的数值模拟[J]. 重庆交通大学学报, 2013, 32(5): 100-1013.

[14] Liu, C.-H. and Chen, J.M. (2002) Observations of Hysteresis Inflow around Two Square Cylinders in a Tandem Ar-rangement. Journal of Wind Engineering and Industrial Aerodynamics, 90, 1019-1050.
https://doi.org/10.1016/S0167-6105(02)00234-9

[15] 李雪健, 苏中地. 绕串列方柱流动的三维大涡仿真[J]. 计算机仿真, 2014, 31(6): 238-255.

Top