后掠翼身干扰区流动特性及改善措施研究

The Flow Characteristics and Its Melioration of Swept Wing/Body Interference

利用流动显示及表面压力测量方法研究了后掠翼身干扰区的流动特性 ,并研究了用小边条等措施改善干扰区的流动特性的效果。结果表明 ,随着不同机翼后掠角、不同迎角及不同Re数对干扰区流动特性的影响 ,流态可以从一涡系变成多涡系 ,由定常变成非定常 ,而且在一定的Re数以后涡系会湍流化 ;翼身干扰区上游的的逆压梯度是导致边界层分离的物理原因 ,利用面积很小的边条可以降低干扰区局部的逆压梯度 ,可以导至干扰区的旋涡很弱 ,甚至不出现 。

A flow visualization and pressure distribution measurement test has been performed to better understand the flow characteristics of swept wing/body junctions. Different small strakes have been used to ameliorate the characteristics. The results show that with increase of the angle of attack and the Reynolds numbers, two or three horseshoe vortices may appear. The steady vortex system may be changed into the unsteady vortex system and may be transferred into turbulent flow. With increase of the sweptangle of the wing, intensity and the size of the horseshoe vortex is decreased. It has been shown that the pressure gradient upstream of the wing/body junctions is the cause of the boundary layer separation. When the swept angle is decreased the pressure gradient can be also reduced. The small strake is able to decrease the pressure gradient and makes the vortex weaken or even disappear upstream of the interference zone.