前缘切口对翼伞气动性能的影响

Effect on parafoil aerodynamic performance of leading edge

对带不同前缘切口和弧面下反角以Clark-Y翼型为基础翼型的翼伞分别进行了二维和三维的数值模拟,详细分析了前缘切口和弧面下反角对翼伞气动性能的影响.结果表明:前缘切口在增强翼伞的滑翔性能的同时,导致升力系数减小,阻力系数增加,且切口越大,升力系数损失越严重;前缘切口的"唇部"可有效降低翼伞型阻;弧面下反角越大,翼伞升力损失越大;所推导的修正LLT(lift line theory)模型,在中小迎角范围内,具有很高的精度.

Two-dimensional and three-dimensional steady flow field of parafoils with profile based on Clark-Y and with different leading edges and arc-anhedral angles were numerically simulated without considering the impact of flexibility,so as to study the effect of leading edge and arc-anhedral angle on parafoil aerodynamic performance.Results show that while enhancing the glide performance,the leading edge cut leads to the decrease of lift coefficient and increase of drag coefficient,and the reduction of lift coefficient gets more severe with the increase of cut size;the lip located in leading edge cut can effectively reduces the profile drag of parafoil;the lift reduction of parafoil increases as the value of arc-anhedral angle gets larger;in addition,this modified LLT（lift line theory）model exhibits high accuracy within the range of small and median angles of attack.