编队飞行风洞实验研究

在1m非定常风洞中开展了两机编队飞行试验研究。前机采用尾支撑转接垂直叶型支杆与坐标架连接，可以实现相对位置（纵向、侧向和垂向间距）的精确改变；后机通过尾支撑连接到风洞的主支撑机构上，可以实现迎角的变化。采用内式六分量应变天平测量后机的气动力受前机尾涡流影响的变化情况，对后机的绕流场进行了PIV测量。试验中使用了2组模型，一组是简化的翼身组合体模型，另一组是翼身融合体飞翼布局模型。结果表明:当前机翼尖涡靠近后机翼面时，后机的升阻比变化较明显；当前机翼尖涡靠近后机翼尖时，后机可获得最大升阻比；前机迎角增大时，后机的升阻特性有较明显变化；当后机的迎角大于8°时，其升阻比基本不受前机影响。

Investigation on formation flight in wind tunnel

An investigation on two aircrafts in formation flight was conducted in 1m unsteady wind tunnel. The leading aircraft was supported by a tail sting which was jointed to a vertical vane rod mounted on a frame of axes to achieve different relation positions accurately (including longitudinal spacing, lateral spacing and vertical spacing). The following aircraft was supported by primary support system of the wind tunnel to change its angle of attack. The aerodynamic forces and moments were measured by an inner six-component strain-gage balance, and the interaction flow structures were measured by a PIV system. Two sets of models were involved. One was the simple wing-body configuration and the other was flying wing configuration. Results show that lift-to-drag ratio of the following aircraft changes remarkably as the wingtip vortex of the leading aircraft approaches the following aircraft's wing, and when the vortex is close to the following aircraft's wingtip, the following aircraft can obtain the maximum lift-to-drag ratio. The following aircraft's aerodynamic characteristics change remarkably as the leading aircraft's angle of attack increases. However, lift-to-drag ratio of the following aircraft changes little when its angle of attack is bigger than 8° even with the presence of the leading aircraft.