王皓田, 朱杨柱, 车学科, 等. S1223翼型低雷诺数下分离泡及气动特性[J]. 空气动力学学报, 2021, 39(3): 90−98. doi: 10.7638/kqdlxxb-2020.0075
引用本文: 王皓田, 朱杨柱, 车学科, 等. S1223翼型低雷诺数下分离泡及气动特性[J]. 空气动力学学报, 2021, 39(3): 90−98. doi: 10.7638/kqdlxxb-2020.0075
WANG H T, ZHU Y Z, CHE X K, et al. Separation bubble and aerodynamic characteristics of S1223 airfoil at low Reynolds numbers[J]. Acta Aerodynamica Sinica, 2021, 39(3): 90−98. doi: 10.7638/kqdlxxb-2020.0075
Citation: WANG H T, ZHU Y Z, CHE X K, et al. Separation bubble and aerodynamic characteristics of S1223 airfoil at low Reynolds numbers[J]. Acta Aerodynamica Sinica, 2021, 39(3): 90−98. doi: 10.7638/kqdlxxb-2020.0075

S1223翼型低雷诺数下分离泡及气动特性

Separation bubble and aerodynamic characteristics of S1223 airfoil at low Reynolds numbers

  • 摘要: 采用表面测压技术,测量了低雷诺数下(Re = 6.0×104、1.0×105、2.0×105) S1223翼型的表面压力分布,通过时均化处理及瞬态处理方法,分别获得了翼型稳态和瞬态压力系数、升力系数,分析了流场结构随雷诺数及攻角的变化规律,研究了雷诺数及攻角对翼型升力的影响机理。结果表明,从时均升力系数随攻角的变化规律来看,S1223翼型在低雷诺数下存在“静态滞回”效应。攻角由负逐渐增大至0°时,下翼面由完全分离转变为出现层流分离泡,随后分离泡逐渐减小直至消失,导致升力系数斜率呈现随攻角逐渐增大的非线性现象。当攻角超过临界攻角后,不同雷诺数下翼型流场结构随攻角的变化规律存在本质不同,Re = 6.0×104和1.0×105时,翼型周围流场迅速发生大范围流动分离,升力系数迅速减小;而Re = 2.0×105时,上翼面周期性生成短泡,引发低频振荡现象,升力系数呈现准周期性变化,α = 16°时上翼面时均流场呈现40%弦长的长泡结构。

     

    Abstract: The surface pressure distribution of the S1223 airfoil at low Reynolds numbers (Re = 6.0×104, 1.0×105 and 2.0×105) was measured using the surface pressure measurement technique. Both time-averaging and transient processing methods were used to obtain the steady and transient pressure/lift coefficients on the airfoil. Combined with the flow structure analysis, the influence mechanism of the Reynolds number and the angle of attack on the lift of the airfoil was studied. According to the variation of time averaged lift coefficient with the angle of attack, S1223 airfoil exibits a "static hysteresis" effect at low Reynolds numbers. The results show that under negative angles of attack, the lift coefficient curve shows a nonlinear phenomenon where its slope gradually increases. When the angle of attack is increased from a negative value, the lower wing surface changes from the state of complete separation to that of laminar separation bubbles, then the separation bubbles gradually shrink until disappeared, resulting in the slope of the lift coefficient curve gradually increasing with the angle of attack. When the angle of attack exceeds the stall value, the flow structures on the S1223 airfoil under different Reynolds numbers are essentially different. At Re = 6.0×104 and 1.0×105, the flow field around the airfoil rapidly undergoes large-scale flow separation, and the lift coefficient decreases sharply; at Re = 2.0×105, short bubbles on the upper wing surface are generated periodically, causing low-frequency oscillations, and the lift coefficient exhibits a quasi-periodic variation. In the meantime, the averaged flow field on the upper wing surface exhibits a long bubble structure with a chord length of 40%.

     

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