考虑阶跃型地面的翼型前飞气动特性影响研究

Influence of Aerodynamic Characteristics of Airfoil Forward Flight Considering Step-Type Ground

翼型前飞过程中,地面效应带来的气动力影响难以忽略,尤其在地面结构产生突变时翼型的气动性能必然产生较大变化.通过NACA4412翼型算例,研究了翼型前飞过程中阶跃型地面引起的气动性能影响,分析高度和迎角两种因素与翼型气动性能的相关性.结果表明:在阶跃型地面作用下,翼型前飞在地面效应缺失时会引起翼型升阻比陡降,且与离地高度存在线性关系.离地攻角则与气动性能突变之间存在相反关系,即翼型脱离地面时需维持较大迎角才能减弱气动性能陡变效应,舰载机的起降过程属于典型的阶跃型地面.基于上述结果,为地面效应影响下翼型的气动设计提供参考.

The aerodynamic influence of ground effects during forward flight is difficult to ignore,especially when there is a sudden change in the ground structure.The aerodynamic performance of the airfoil during forward flight is investigated using the NACA4412 airfoil,the correlation between two factors,i.e.,height and angle of attack,and the aerodynamic performance of the airfoil are analyzed.The results show that under the effect of step-type ground,the wing forward flight causes a steep drop in lift-to-drag ratio when the ground effect is absent,and there is a linear relationship with the height above the ground.The angle of attack from the ground has an inverse relationship with the sudden change in aerodynamic performance,i.e.,the airfoil needs to maintain a large angle of attack when it leaves the ground in order to reduce the steep change in aerodynamic performance.The take-off and landing process of a shipboard aircraft is typical of a step-type ground.This paper provides a reference for the aerodynamic design of an airfoil under the influence of ground effects.