An in-depth study on the dynamic aerodynamic performance of the pitch oscillating airfoil is carried out in the two-dimensional test section of the NF-3 low-speed wind tunnel of Northwestern Polytechnical University. The test model is a span-wise three-section force measurement model, and the force measurement is only performed in the middle section of the model to reduce the influence of the sidewall interference of the wind tunnel. In the experiment, the transient angle of attack of the model is collected; the inertial force and pitch moment on the middle section of the model are calculated and subtracted from the data collected by the balance to correct the influence of the model's inertia on the results. The results show that the angle of attack exceeding the positive or negative static stall angles of attack is a necessary condition for the lift and pitch moment coefficients to produce a large hysteresis loops. As the oscillation reduced frequency increases, the dynamic stall is delayed, the lift coefficient hysteresis loop increases, the drag coefficient increases, and the pitch moment coefficient near the maximum angle of attack decreases. When the angle of attack is less than the static angle of attack of stall or exceeds a small range, with the increase of the reduced frequency of the airfoil oscillation, the pitch moment coefficient of the airfoil decreases when it goes up and increases when it goes down. With the increase of the oscillation amplitude, the hysteresis loops of both dynamic lift coefficient and pitch moment coefficient of the oscillating airfoil increase. As the average angle of attack increases, the angle of attack of airfoil enters the positive stall zone more, the lift coefficient hysteresis loop increases, and the minimum pitch moment coefficient decreases. The Reynolds number has no obvious effect on the hysteresis loop of lift, drag and pitch moment coefficients; however, in the downward process, as the Reynolds number increases, the lift recovery advances, and the hysteresis loop decreases.
Key words
wind turbines /
airfoils /
wind tunnels /
dynamic loads /
aerodynamic stalling /
force measurement /
inertia correction
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] CARR L W.Progress in the analysis prediction of dynamic Stall[J]. Journal of aircraft, 1988, 25(1): 6-17.
[2] LEISHMAN J G.Principles of helicopter aerodynamics[M]. Cambridge: Cambridge University Press, 2000: 302-318.
[3] CONLISK A T.Modern helicopter rotor aerodynamics[J]. Progress in aerospace sciences, 2001, 37(5): 419-476.
[4] HAM N D.Aerodynamic loading in a two-dimensional airfoil during dynamic stall[J]. AIAA journal, 1968,6(10): 1927-1934.
[5] CROSKEY W J.Viscous-inviscid interaction on oscillating airfoil in subsonic flow[J]. AIAA journal, 1982, 20(2):167-174.
[6] CARR L W, MCALISTER K W,MCCROSKEY W J.Analysis of the development of dynamic stall based on oscillating airfoil experiments[R]. NASA TN D-8382, 1977.
[7] MCALISTER K W, CARR L W, MCCROSKEY W J.Dynamic stall experiments on the NACA0012 airfoil[R]. NACA TP 1100, 1978.
[8] CONGER R N, RAMAPRIAN B R.Pressure measurements on a pitching airfoil in a water channel[J]. AAIA journal, 1994, 32(1): 108-115.
[9] PIZIALI R A.2-D and 3-D Oscillating wing aerodynamics for a range of angles of attack including stall[R]. NASA TM 4632, 1994.
[10] 夏玉顺, 郗忠祥, 周瑞兴, 等. NACA0012翼型动态失速特性和测压方法的研究[J]. 航空学报, 1996, 17(7):25-30.
XIA Y S, XI Z X, ZHOU R X, et al.Dynamic of stall characters of NACA0012 airfoil and investigations of dynamic pressure measure methods[J]. Acta aeronautica et astronautica sinica, 1996, 17(7): 25-30.
[11] 惠增宏, 王龙, 徐倩. 风力机翼型动态测压实验技术研究[J]. 实验流体力学, 2012, 26(4): 6-10.
HUI Z H, WANG L, XU Q.Dynamic pressure measurement techniques on wind turbine airfoil[J]. Journal of experiments in fluid mechanic, 2012, 26(4): 6-10.
[12] PANDA J, ZAMAN K B M Q. Experimental investigation of the flow field of an oscillating airfoil and estimation of lift from wake surveys[J]. Journal of fluid mechanics,1994, 265: 65-95.
[13] WERNER P,GEISSLER W, RAFFEL M, et al.Experimental and numerical investigations of dynamic stall on a pitching airfoil[J]. AIAA journal, 1996, 34(5): 982-989.
[14] OSHIMA H,RAMAPIAN B R.Velocity measurements over a pitching airfoil[J]. AIAA journal, 1997, 35(1):119-126.
[15] 王清, 招启军, 赵国庆. 旋翼翼型动态失速流场特性PIV实验研究及L-B模型修正[J]. 力学学报, 2014, 46(4): 631-635.
WANG Q, ZHAO Q J, ZHAO G Q.PIV experiments on flow field characteristic of rotor airfoil dynamic stall and modifications of L-B model[J]. Chinese journal of theoretical and applied mechanics, 2014, 46(4): 631-635.
[16] 汤瑞源, 华宪明, 吴水健. 振荡翼型动态失速风洞实验研究[J]. 南京航空学院学报, 1992, 24(5): 506-512.
TANG R Y, HUA X M, WU S J.Experimental study of dynamic stall on an oscillating airfoil[J]. Journal of Nanjing Aeronautic Institute, 1992, 24(5): 506-512.
[17] TSANG K Y K. Direct force measurements of a two-dimensional airfoil undergoing dynamic stall[D]. Hong Kong: Hong Kong Polytechnic University, 2006.
[18] RIVAL D,TROPEA C.Characteristics of pitching and plunging airfoils under dynamic-stall conditions[J]. Journal of aircraft, 2010, 47(1): 80-86.
[19] 林永峰, 黄建萍, 黄水林, 等. 直升机旋翼翼型动态失速特性实验研究[J]. 航空科学技术, 2012(4): 25-28.
LIN Y F, HUANG J P, HUANG S L, et al.Experimental investigation of rotor airfoil dynamic stall characteristics[J]. Aeronautical science and technology, 2012(4):25-28.
[20] 焦予秦, 解亚军, 高永卫, 等. 整体框架三段式翼型风洞动态测力实验模型: CN201921940956.4[P].2020-06-09.
JIAO Y Q, XIE Y J, GAO Y W, et al. Three-section airfoil experimental model with integral frame for dynamic force measurement in wind tunnel: CN201921940956.4[P].2020-06-09.
PDF(1732 KB)
