大展弦比柔性机翼气动特性分析

Aerodynamic characteristic analysis of high-aspect ratio elastic wing

长航时无人机在飞行过程中受气动载荷影响,其大展弦比机翼产生弯曲和扭转变形,这种弹性变形严重影响飞机的飞行性能和飞行安全,不能将此种飞机机翼当作传统的刚性机翼进行气动分析.针对一真实复合材料大展弦比前掠机翼,采用气动/结构一体化的分析方法,利用计算流体动力学(CFD)软件FLUENT和计算结构动力学(CSD)软件NASTRAN联合求解,研究了在不同载荷情况下大展弦比柔性机翼静气动弹性变形对机翼气动特性的影响.结果表明,大展弦比无人机机翼受载变形后升阻比降低,滚转力矩和偏航力矩显著增大,对飞机的纵向和横侧向气动性能产生不利影响,同时也证明此CFD/CSD耦合计算方法可以应用到柔性机翼的气动/结构一体化设计中.

The aerodynamic performance and flying safety of long-endurance unmanned aerial vehicle （UAV） are largely affected by the aeroelastic distortion of its high-aspect ratio wing. High-aspect ratio wing of UAV is bended and twisted by the air load during flight and couldn＇t be treated as a traditional rigid wing. The effect of static aeroelastic distortion to the aerodynamic characteristic for a real high-aspect ratio sweepforward wing of composite material under different load statuses was analyzed. The integrated design method combined aerodynamic with structural was adopted in this analysis using associated computational fluid dynamics （CFD） program FLUENT and computational structual dynamics （CSD） program NASTRAN. The result shows a liftdrag ratio drop and a remarkable increase on roiling and yawing moments which affect the portrait and lateral aerodynamic performance of UAV negatively. The result also shows that the CFD/CSD coupling computational methodology is reliable to be used aerodynamic-structural integrated design of elastic wing.