悬停状态双旋翼气动干扰与安全间隔研究*

为了保证旋翼无人机编队飞行时的安全性，探究双旋翼间的气动干扰作用，采用计算流体力学仿真的方法，研究悬停状态下不同间隔的双旋翼流场干涉特征和气动参数变化。首先通过单旋翼实验和数值结果对比，验证数值方法的有效性；然后分析不同间隔双旋翼流场干涉的截面速度分布和涡量分布特征；最后讨论双旋翼作用下间隔对气动参数的影响。研究结果表明:气动干扰主要影响2#旋翼的流场特征和气动参数；当两旋翼无横向间隔时，流场可保持对称性，气动力变化主要表现为拉力和扭矩的降低；当横向间隔0.5D≤X≤1.0D时，2#旋翼速度场和涡量场扩散范围受限，其流场出现明显非对称特征；在X=0.5D且1.0D≤Z≤3.0D间隔时2#旋翼受到显著俯仰力矩作用，为悬停较危险区域。

Research on aerodynamic interaction and safety separation of twin rotors under hovering state

In order to ensure the safety in the formation flight of rotor unmanned aerial vehicles (UAVs) and explore the aerodynamic interaction effect between twin rotors,the flow field interference characteristics and aerodynamic parameters variation of twin rotors with different separations under the hovering state were studied by using the computational fluid dynamics (CFD) simulation method.Firstly,the effectiveness of numerical method was validated by comparing the experimental results of single rotor with the numerical results.Secondly,the cross-section velocity and vorticity distribution characteristics of flow field interference for twin rotors with different separations were analyzed.Finally,the influence of separation on the aerodynamic parameters of twin rotors was discussed.The results showed that the aerodynamic interaction mainly affected the flow field characteristics and aerodynamic parameters of 2# rotor.When there was no lateral separation between twin rotors,the flow field could maintain symmetry,and the aerodynamic force variation mainly represented as the reduction of tensile force and torque.The diffusion range of velocity field and vorticity field of 2# rotor was limited for the lateral separation 0.5D≤X≤1.0D,and the flow field presented the obvious asymmetric characteristic.The 2# rotor was affected by the significant effect of pitching moment for the separation of X=0.5D and 1.0D≤Z≤3.0D,where was a more dangerous area for hovering.