Effects of end condition on aerodynamic force distribution on a skewed circular cylinder
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摘要: 在有限长度圆柱气动力测试风洞试验中，端部状态的变化对气动力有很大影响。在雷诺数为6.43×104时，通过刚性模型风洞测压试验对3种端部状态下的斜置圆柱气动力特性进行研究，基于平均风压系数沿斜置圆柱的轴向和周向分布规律，分析端部状态对斜置圆柱气动力测试结果的影响。结果表明：斜置圆柱表面风压沿轴向可分为近上游端部区、中间区和近下游端部区；由于马蹄涡的存在，在近上游端部区的背风面，风压沿轴向有一个突变，端部状态对马蹄涡强度有很大影响；在中间区，背风面风压沿轴向出现交替变化，可能是由于在近上游端部区形成的旋涡受到轴向流作用向中间区流动导致的，端部状态对交替风压变化的幅度和阻力系数有很大影响；当下游端部封闭时，近下游端部区的迎风面和背风面风压都会出现突变，且迎风面的突变幅度更大，下游端板对近下游端部区迎风面的风压分布影响更大。Abstract: The change of the end conditions has significant influences on the aerodynamic forces when a finite length cylinder is tested in the wind tunnel for its aerodynamic forces. In the present study, the characteristics of aerodynamic forces on an oblique cylinder with various end conditions at Reynolds number of 6.43×104 are studied through a rigid model pressure test in a wind tunnel. Using the wind pressure distribution along the length of the cylinder, the effects of end conditions on aerodynamic forces on the oblique circular cylinder are revealed. The results show that the wind pressure on the oblique cylinder could be classified into three states along the length of the cylinder, that the state near the upstream end plate, the state at the middle and the state near the downstream end plate. The wind pressure on the leeward near upstream end plate has a significant variation (convex) due to the existence of the horseshoe vortex. The existence of the end plates significantly influences the strength of the horseshoe vortex. At the middle state, the wind pressure on the leeward varies alternately along the length, which is probably induced by the motion of the horseshoe vortex through the axial flow. The end conditions also influence the amplitude of the alternative wind pressure at the leeward and the local drag coefficient on the cylinder. Near the downstream end plate state, wind pressure on the windward and leeward varies sharply when the downstream end plate is closed. The downstream end plate has a more significant influence on the wind pressure distribution at the windward than at the leeward.
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图 7 上下测点的风压系数分布
Figure 7. Wind pressure coefficient distribution at both flanks, Cpnd and Cpnu
图 10 上下测点的风压系数分布
Figure 10. Wind pressure coefficient distribution at both sides, Cpnd and Cpnu
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[1] Sarpkaya T. A critical review of the intrinsic nature of vortex-induced vibrations[J]. Journal of Fluids and Structures, 2004, 19(4):389-447. doi: 10.1016/j.jfluidstructs.2004.02.005 [2] Stansby P K. The effects of end plates on the base pressure coefficient of a circular cylinder[J]. Aeronautical Journal, 1974, 78:36-37. https://www.researchgate.net/publication/285353239_The_effects_of_end_plates_on_the_base_pressure_coefficient_of_a_circular_cylinder?_sg=P7GV4ls58QYc4Hw9DIoV_okPNY0HGf_qoF6FQsJNyU-1RYTtjYyPlTMKJdnOslzRDTxFVXUvi-bKf8Q4bVz3NQ [3] Fox T A, West G S. On the use of end plates with circular cylinders[J]. Experiments in Fluids, 1990, 9(4):237-239. doi: 10.1007/BF00190426 [4] Inagaki A, Mino Y, Iwamoto M, et al. Aspect ratio and end wall effects on the surface pressure coefficient of a circular cylinder[J]. Journal of Fluid Science and Technology, 2014, 9(3):JFST0062-JFST0062. doi: 10.1299/jfst.2014jfst0062 [5] 郑云飞, 刘庆宽, 马文勇, 等.端部状态对斜拉索节段模型气动特性的影响[J].工程力学, 2017, 34(S1):192-196. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gclx2017z1033Zheng Y F, Liu Q K, Ma W Y, et al. Influence of end conditions on aerodynamic force of section models for stay-cables[J]. Engineering Mechanics, 2017, 34(S1):192-196. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gclx2017z1033 [6] Shirakashi M, Hasegawa A, Wakiya S. Effect of the secondary flow on Karman vortex shedding from a yawed cylinder[J]. Bulletin of JSME, 1986, 29(250):1124-1128. doi: 10.1299/jsme1958.29.1124 [7] Matsumoto M. Vortex shedding of bluff bodies:a review[J]. Journal of Fluids and Structures, 1999, 13(7-8):791-811. doi: 10.1006/jfls.1999.0249 [8] Hayashi T, Kawamura T. Non-uniformity in a flow around a yawed circular cylinder[J]. Flow Measurement and Instrumentation, 1995, 6(1):33-39. https://www.researchgate.net/publication/245218732_Non-uniformity_in_a_flow_around_a_yawed_circular_cylinder [9] 顾明, 杜晓庆.不同风向角下斜拉桥拉索模型测压试验研究[J].振动与冲击, 2005, 24(6):5-8, 20. doi: 10.3969/j.issn.1000-3835.2005.06.002Gu M, Du X Q. Testing study on wind pressures on a stayed cable model under different wind angles[J]. Journal of vibration and shock, 2005, 24(6):5-8, 20. doi: 10.3969/j.issn.1000-3835.2005.06.002 [10] 李寿英, 顾明.斜、直圆柱绕流的CFD模拟[J].空气动力学学报, 2005, 23(2):222-227. doi: 10.3969/j.issn.0258-1825.2005.02.017Li S Y, Gu M. Numerical simulation for flow around perpendicular and oblique circular cylinders[J]. Acta Aerodynamica Sinica, 2005, 23(2):222-227. doi: 10.3969/j.issn.0258-1825.2005.02.017 [11] Ma W Y, Liu Q K, Du X Q, et al. Aerodynamic forces and galloping instability for a skewed elliptical cylinder in a flow at the critical Reynolds number[J]. Fluid Dynamics Research, 2017, 49(4):045509. doi: 10.1088/1873-7005/aa7704 [12] 马文勇, 刘庆宽, 刘小兵, 等.风洞试验中测压管路信号畸变及修正研究[J].实验流体力学, 2013, 27(4):71-77. doi: 10.3969/j.issn.1672-9897.2013.04.013Ma W Y, Liu X K, Liu X B, et al. Study on correction and distortioneffects caused by tubing systems of pressure measurements in wind tunnel[J]. Journal of Experiments in Fluid Mechanics, 2013, 27(4):71-77. doi: 10.3969/j.issn.1672-9897.2013.04.013 [13] Zdravkovich M M. Flow around circular cylinder[M]. Oxford:Oxford University Press, 1997. [14] Humphreys J S. On a circular cylinder in a steady wind at transition Reynolds numbers[J]. Journal of Fluid Mechanics, 1960, 9(4):603-612. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=S0022112060001341 [15] 郑云飞, 刘庆宽, 马文勇, 等.端板对二维矩形风洞试验模型气动特性的影响[J].实验流体力学, 2017, 31(3):38-45. http://www.syltlx.com/CN/abstract/abstract11022.shtmlZheng Y F, Liu Q K, Ma W Y, et al. Effects of end plates on aerodynamic force of rectangular prisms in wind tunnel test[J]. Journal of Experiments in Fluid Mechanics, 2017, 31(3):38-45. http://www.syltlx.com/CN/abstract/abstract11022.shtml [16] ESDU. Mean forces, pressures and flow field velocities for circular cylindrical structures: Single cylinder with two-dimensional flow, ESDU 80025[R]. London, UK: Engineering Sciences Data Unit, 1980. [17] 梁辉, 姜胜耀, 段日强.有限长倾斜圆柱绕流的展向特性研究[C]//第十四届全国反应堆热工流体学术会议暨中核核反应堆热工水力技术重点实验室2015年度学术年会论文集. 2015.Liang H, Jiang S Y, Duan R Q. Spanwise Characteristics of flow crossing a yawed circular cylinder[C]//Proc of the 14th National Symposium on reactor thermal fluid. 2015. [18] Hayashi T, Yoshino F, Waka R, et al. Pressure distribution on the surface of a yawed circular cylinder (the effect of end-plates on the spanwise pressure distribution)[J]. Transactions of the Japan Society of Mechanical Engineers Series B. 1992, 58(545):71-78. doi: 10.1299/kikaib.58.71 -
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