低雷诺数下机翼气动特性研究及控制
收稿日期: 2015-05-18
修回日期: 2015-07-18
网络出版日期: 2015-07-30
基金资助
江苏高校优势学科建设工程资助项目
Aerodynamic characteristics and flow control on a rectangular wing at low Reynolds number
Received date: 2015-05-18
Revised date: 2015-07-18
Online published: 2015-07-30
Supported by
A Project Funded by the Priority Academic Progran Development of Jiangsu Higher Education Institutions
高空长航时无人飞行器(HALE UAV)由于飞行环境空气稀薄、雷诺数低导致其气动性能恶化,如何通过流动控制改善机翼低雷诺数气动性能受到越来越多的关注。在低速风洞中通过测力、测压和边界层测试等试验技术开展了NACA 633-421直机翼模型气动特性试验和流动控制研究。天平测力结果表明:随雷诺数降低(Re<1.4×105)机翼气动特性迅速恶化;最大升力系数损失严重,失速迎角急剧降低;分析翼面压力分布结果显示,机翼表面产生层流分离泡(LSB),其长度变化、位置前移和最终发生破裂的发展过程是导致机翼低雷诺数气动性能恶化的主要原因。采用合成微射流(Micro-SJ)对翼面层流分离泡进行流动控制,失速迎角推迟了11°,机翼最大升力系数由0.59提升至1.10,最大升阻比增加了13.6%。合成微射流控制具有选频特性,驱动频率f=200~400 Hz的合成微射流控制效果最佳,更易促进分离剪切层提前转捩,形成湍流再附,使得层流分离泡长度缩短。
左伟 , 顾蕴松 , 王奇特 , 郑越洋 , 刘源 . 低雷诺数下机翼气动特性研究及控制[J]. 航空学报, 2016 , 37(4) : 1139 -1147 . DOI: 10.7527/S1000-6893.2015.0208
It is found that the flight environment in thin atmosphere and at low Reynolds number leads to the drop of high-altitude long-endurance unmanned aerial vehicles (HALE UAV) aerodynamic performance, and as a result, how to improve it with flow control has drawn greater attention of researchers. An experimental investigation on the aerodynamic characteristics and flow control of a NACA 633-421 rectangular wing at low Reynolds number is conducted in a low-speed wind tunnel with force measurement,pressure measurement and boundary layer test. It is shown from force measurement result that a sharp deterioration of aerodynamic characteristics of NACA 633-421 wing occurs with the Reynolds number decreasing(Re<1.4×105), which includes severe losses of the maximum lift coefficient with respect to higher Reynolds numbers and the sharp decrease of stall angle. Pressure distribution on upper surface reveals that the emergence and development process of a laminar separation bubble (LSB), which moves forward to the wing leading edge, becomes shorter in length with increasing angles of attack and bursts at the stall angle, finally cause the sharp deterioration of aerodynamic characteristics. The micro synthetic jet (Micro-SJ) is used to control the flow structure of laminar separation bubbles, as a result of which the maximum lift coefficient increases from 0.59 to 1.10, the stall is delayed by 11° and the maximum lift-drag ratio is improved by 13.6% meanwhile. The active flow control of Micro-SJ possesses frequency selectivity, in which case the Micro-SJ at the frequencies between 200 Hz to 400 Hz have the best flow control effects to promote the transition of the separated shear layer and to shorten the length of laminar separation bubbles.
[1] GAD-EL-HAK M. Micro-air-vehicles:Can they be controlled better?[J]. Journal of Aircraft, 2001, 38(3):419-429.
[2] 李锋, 白鹏, 石文, 等. 微型飞行器低雷诺数空气动力学[J]. 力学进展, 2007, 37(2):257-268. LI F, BAI P, SHI W, et al. Low Reynolds number aerodynamics of micro air vehicles[J]. Advances in Mechanics, 2007, 37(2):257-268(in Chinese).
[3] LISSAMAN P B S. Low-Reynolds-number airfoils[J]. Annual Review of Fluid Mechanics, 1983, 15(1):223-239.
[4] 王松涛, 刘勋, 周逊, 等. 低压涡轮低雷诺数条件下气动性能分析[J]. 汽轮机技术, 2011, 53(5):324-327. WANG S T, LIU X, ZHOU X, et al. Aerodynamic performance analysis of low pressure turbine at low Reynolds numbers[J]. Turbine Technology, 2011, 53(5):324-327(in Chinese).
[5] TANI I. Low-speed flows involving bubble separations[J]. Progress in Aerospace Sciences, 1964, 5:70-103.
[6] GASTER M. The structure and behaviour of laminar separation bubbles:Reports and Memoranda 3595[R]. London:Her Majesty's Stationery Office, 1969.
[7] HORTON H P. Laminar separation bubbles in two and three dimensional incompressible flow[D]. London:Queen Mary, University of London, 1968.
[8] FITZGERALD E J, MUELLER T J. Measurements in a separation bubble on an airfoil using laser velocimetry[J]. AIAA Journal, 1990, 28(4):584-592.
[9] ARENA A V, MUELLER T J. On the laminar separation, transition, and turbulent reattachment of low Reynolds number flows near the leading edge of airfoils:AIAA-1979-0004[R]. Reston:AIAA, 1979.
[10] MUELLER T J, BATIL S M. Experimental studies of separation on a two-dimensional airfoil at low Reynolds numbers[J]. AIAA Journal, 1982, 20(4):457-463.
[11] POHLEN L J, MUELLER T J. Boundary layer characteristics of the Miley airfoil at low Reynolds numbers[J]. Journal of Aircraft, 1984, 21(9):658-664.
[12] MUELLER T J. The influence of laminar separation and transition on low Reynolds number airfoil hysteresis[J]. Journal of Aircraft, 1985, 22(9):763-770.
[13] LANG M, RIST U, WAGNER S. Investigations on controlled transition development in a laminar separation bubble by means of LDA and PIV[J]. Experiments in Fluids, 2004, 36(1):43-52.
[14] BURGMANN S, SCHRÖDER W. Investigation of the vortex induced unsteadiness of a separation bubble via time-resolved and scanning PIV measurements[J]. Experiments in Fluids, 2008, 45(4):675-691.
[15] 叶建, 邹正平, 陆利蓬, 等. 低雷诺数下翼型前缘流动分离机制的研究[J]. 北京航空航天大学学报, 2004, 30(8):693-697. YE J, ZHOU Z P, LU L P, et al. Investigation of separation mechanism for airfoil leading edge flow at low Reynolds number[J]. Journal of Beijing University of Aeronautics and Astronautics, 2004, 30(8):693-697(in Chinese).
[16] 白鹏, 崔尔杰, 李锋, 等. 对称翼型低雷诺数小迎角升力系数非线性现象研究[J]. 力学学报, 2006, 38(1):1-8. BAI P, CUI E J, LI F, et al. Study of the nonliner lift coefficient of the symmetrical airfoil at low Reynolds number near the 0° angle of attack[J]. Chinese Journal of Theoretical and Applied Mechanics, 2006, 38(1):1-8(in Chinese).
[17] 张强, 杨永. 绕翼型低雷诺数流动的数值分析研究[J]. 空气动力学学报, 2006, 24(4):482. ZHANG Q, YANG Y. Numerical analysis of low Reynolds number flow over airfoil[J]. Acta Aerodynamics Sinica, 2006, 24(4):482(in Chinese).
[18] YARUSEVYCH S, SULLIVAN P E, KAWALL J G. On vortex shedding from an airfoil in low-Reynolds-number flows[J]. Journal of Fluid Mechanics, 2009, 632:245-271.
[19] 关键, 郭正. 绕翼型低雷诺数流动的数值仿真[J]. 科学技术与工程, 2013, 13(24):7275-7281. GUAN J, GUO Z. Numerical simulations of low-Reynolds-number flows over the E387 airfoil[J]. Science Technology and Engineering, 2013, 13(24):7275-7281(in Chinese).
[20] 吴鋆, 李天, 王晋军. 低Reynolds数NACA 0012翼型绕流的流动特性分析[J]. 实验力学, 2014, 29(3):265-272. WU J, LI T, WANG J J. Characteristic analysis of flow around NACA 0012 airfoil in a low-Reynods-number media[J]. Journal of Experimental Mechanics, 2014, 29(3):265-272(in Chinese).
[21] TSUCHIYA T, NUMATA D, SUWA T, et al. Influence of turbulence intensity on aerodynamic characteristics of an NACA 0012 at low Reynolds numbers[C]//51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Reston:AIAA, 2013.
[22] MITRA A, RAMESH O N. The role of laminar separation bubble on low Reynolds number airfoils[C]//51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Reston:AIAA,2013.
[23] THAKE M P, PACKARD N O, BONILLA C H, et al. Low Reynolds number laminar airfoil with active flow control:AIAA-2010-4579[R]. Reston:AIAA, 2010.
[24] 刘沛清, 马利川, 屈秋林, 等. 低雷诺数下翼型层流分离泡及吹吸气控制数值研究[J]. 空气动力学学报, 2013, 31(4):518-524. LIU P Q, MA L C, QU Q L, et al. Numerical investigation of the laminar separation bubble control by blowing/suction on an airfoil at low Re number[J]. Acta Aerodynamics Sinica, 2013, 31(4):518-524(in Chinese).
[25] YANG S L, SPEDDING G R. Separation control by external acoustic excitation at low reynolds numbers[J]. AIAA Journal, 2013, 51(6):1506-1515.
[26] GERAKOPULOS R, BOUTILIER M S H, YARUSEVYCH S. Aerodynamic characterization of a NACA 0018 airfoil at low Reynolds numbers:AIAA-210-4629[R]. Reston:AIAA, 2010.
/
| 〈 |
|
〉 |
CJA