格尼襟翼对低雷诺数翼型流场的影响研究

Study on Impact of Gurney Flaps on Low Reynolds Number Airfoil Flowfield

针对格尼襟翼对低雷诺数翼型流场特性的影响开展了数值仿真研究,建立了包含k-k_L-ω)湍流模型的数值分析方法,并验证了上述模型在低雷诺数流场仿真中的有效性。基于上述模型研究了Eppler387翼型加装1%弦长高度格尼襟翼的流场特性,结果表明加装格尼襟翼后当迎角大于5°时,翼型上表面层流分离泡向前缘移动,其长度大幅减小,有利于流动尽早转捩从而抑制分离。关于后缘涡系形态的研究表明,对称翼型更容易形成双"螺旋式奇点"形态的双涡涡系;而弯度较大、最大弯度位置靠后的翼型更容易形成单涡涡系,即由"螺旋式奇点"与"鞍点式奇点"共同构成的涡系结构。

A numerical study was conducted for the impact of Gurney flaps on flow field of airfoil at low Reynolds numbers. A numerical method adopted k-kL-ω three-equation turbulent model was developed. The availability of this model was validated in low Reynolds number flow simulations. The flow field characteristics of 1% c Gurney flaps was studied based on the model. The results show that the position of laminar separation bubble moves towards lead- ing edge with Gurney flaps as angle of attack greater than 5~. Also the length of laminar separation bubble decreases significantly, so that it is beneficial to transition and the separation of boundary layer. The patterns of trailing edge vortices indicates that, the pattern of double spiral singularity vortices is prone to formation by symmetric airfoil with Gurney flaps, the pattern of single spiral singularity vortex is prone to formation by airfoils of both larger camber and maximum camber location with Gurney flap, and the trailing edge vortices contains the patterns of saddle point singu- larity vortex in the meantime.