跨声速盒式翼布局双翼气动干扰研究

盒式翼布局相对常规布局可以很大程度地减小诱导阻力，同时平滑的升力分布有利于减小跨声速激波阻力，但双翼间的气动干扰是跨声速盒式翼布局存在的主要问题.为掌握跨声速双翼气动干扰特性，选用超临界翼型RAE2822作为双翼翼型，对M=0.75，正负交错两种情况下双翼几何参数对布局升阻特性的影响进行数值研究.结果表明，增大双翼的纵向距离可以减弱双翼间气动干扰，使升阻比提高至无干扰升阻比.其中，前翼在下、后翼在上的负交错布局在双翼纵向距离为1.5倍上翼弦长时即可接近无干扰升阻比，更有利于提升布局的升阻特性.负交错时双翼的垂直间距对布局升阻比影响不大，无翼差角且减小前翼弦长有利于提高升阻比. 

Aerodynamic Interference Between Dual Wings in Transonic Box-wing Aircraft

A box-wing can significantly reduce the induced drag relative to a conventional monoplane, and its smooth lift distribution is beneficial to reduce the transonic wave drag, but aerodynamic interference between dual wings is the principal problem needed to be solved for a transonic box-wing aircraft. In order to improve the transonic aerodynamic interference characteristics, how the geometric parameters affect aerodynamic performance of both positive and negative staggered layout at M=0.75 was numerically investigated, a supercritical airfoil RAE2822 was used for dual wings. Results show that increasing the longitudinal distance can reduce the aerodynamic interference between dual wings and increase the lift-to-drag ratio up to the noninterference case. For a negative staggered layout, which the front wing is under the rear wing, a high lift-to-drag ratio close to noninterference value can be achieved when the longitudinal distance is 1.5 times the upper wing chord length. At this distance, the gap has little effect on the lift-to-drag ratio, without decalage and reducing chord ratio is conducive. The negative staggered layout is confirmed to be more conducive for enhancing the lift-to-drag cha-racteristics.