‘W’型无尾布局流动机理研究

Flow mechanism investigation for 'W' tailless aerodynamic configuration

基于NS方程数值模拟方法,研究了‘W’型无尾布局的流动机理。与参照前掠翼布局相比,‘W’布局优越的气动性能来源于其流动形态的变化:小迎角时,翼身融合升力体设计,使机体表面流动更为通畅,升力增加,机体部件干扰减小,部分补偿了因机身加宽,浸润面积增大带来的摩擦阻力,使总阻力没有明显增加。α≥6°,‘W’布局具有新的流动结构,机翼上表面流动由侧缘涡和前缘涡及其诱导的二次涡所控制,侧缘涡与前缘涡之间产生有利干扰,增强了对机翼表面流动的控制能力,不仅带来涡升力,而且有效控制了前掠翼根部流动分离,是其具有优越纵向气动性能的物理原因。‘W’布局新的流动结构为其横侧气动性能改善奠定了基础,为进一步完善布局设计提供了理论依据。

The flow mechanism of ＇W＇ tailless configuration has been investigated by numerical method based on N-S equations in this paper. The results show that compared with referenced forward swept wing configuration, the excellent aerodynamic characteristics of ＇ W＇ configuration is sourcing from flow pattern changes. At low angles of attack, due to the blended wing body design, flows on the surface are more smooth which brings lift increment. Total drag has no distinct increment because the disturbances between components of configuration are decreased which partially equalizes the increased friction drag caused by enlarged soaked area of widen body. When angle of attack is above 6°, ＇ W＇ configuration possesses new flow pattern. The flow on the upper surface of the wing is controlled by the vortices produced respectively by sidestrake, leading edge and its secondary trailing edge. Favorable interference is produced between vortices of side-strake and leading edge, which enhances the control ability to the flow on the wing surface. This not only affords great vortex lift, but also effectively controls the flow separation at forward swept wing＇s root region. Such new flow pattern is the basic physical springhead for ＇W＇ configuration＇s excellent longitudinal aerodynamic characteristics. ＇W＇ configuration＇s new flow pattern provides the foundation for the improvement of lateral characteristics and perfecting configuration design.