翼身厚度对小展弦比飞翼布局流动特性的影响

Effect of Wing-Body Thickness on Flow Characteristics of Low-Aspect-Ratio Flying-Wing-Configuration

跨音速条件下,激波将导致大后掠飞翼布局出现激波/边界层干扰、激波/前缘涡干扰等复杂流动现象,对其流动特性、气动性能产生严重影响。本文采用数值模拟方法研究了跨音速时小展弦比飞翼布局流动特性随迎角的演化,并分析了翼身厚度对前缘涡流动的影响。计算结果表明:在无前缘涡区,翼身厚度在机头处引起侧洗作用,在尾部出现激波/边界层干扰现象,导致流动分离;在前缘涡发展区,翼身厚度的侧洗作用使飞翼模型前缘涡形成较晚,影响区域减小,但使其前缘涡发展较快,强度增大,在背风侧诱导的吸力增加,从而使前缘涡涡升力基本不变;同时,侧洗作用导致翼身背风侧激波位置前移,诱导前缘涡破裂,使涡破裂迎角大幅减小。本文研究为大后掠飞翼布局气动布局设计和流动机理分析提供了基础。

There are complex flows such as the shock-boundary layer interaction and the shock-leading edge vortex interaction in the highly swept flying-wing configuration at transonic speed, and the flows have serious effect on the flow and erodynamic characteristics. To compare the flow detail of the thin body model and the thick body model, the effect of the wing-body thickness on flow characteristics and the flow mechanism are analyzed by the simulation method. The results show that. At the small attack angle, there is a sidewash effect in the nose and shock-boundary layer interaction which leads to a flow separation in tail due to the quick tail contraction~ at the middle attack angle, the sidewash effect of wing-body thickness makes the leading vortex appear later and the effect zone to be smaller, but it also makes the vortex strength and the wall suction increase, and the effects make the vortex lift change lit- tle. The shock in the middle model due to the wing-body thickness would pass through the leading edge vortex and induce the leading edge vortex breakdown, which makes the vortex breakdown angle and vor- tex lift to be reduced.