The current rotor rig for single rotor test is modified for the experiment of tandem twin rotors. By the PIV technique, the measurements on the rotor blade-tip vortices for tandem rotors in both hover and forward flight have been carried out. The interactions between the twin rotors and their influences on blade-tip vortices are investigated by altering the longitudinal and axial distances between the twin rotors and thus changing the overlapping area. It is shown that the axial displacement of the tip vortex gradually increases with the longitudinal distances between the two rotors in hover, but the change of radial displacement of the tip vortex is not the same, and it reaches the minimum value when the longitudinal distance is about equal to 1. 8R. On the other hand, when the axial distance between the two rotors is modified, the tip-vortex displacement in axial and radial directions are also changed, but the changs are smaller.%将现有单旋翼实验台进行改装,以适合于纵列式双旋翼的实验研究.基于PIY技术,针对悬停和前飞状态下的纵列式双旋翼时的桨尖涡特性进行了测量.通过改变前后旋翼的水平和轴向间距,调整两旋翼之间的重叠区域,研究了不同气动布局纵列式双旋翼干扰状态下的尾迹结构,并与单旋翼进行了对比.结果表明:悬停状态,随两旋翼纵向间距的增加,桨尖涡的轴向位移也逐渐增大,但桨尖涡径向位移并不是随纵向间距的改变而规律变化,在纵向间距为1.8R附近时最小;而双旋翼轴向间距的变化对桨尖涡的径向和轴向位移均有影响,但变化都不是很大.
展开▼
