后缘小翼对旋翼气动特性的控制机理及参数分析

针对后缘小翼（TEF）的典型运动参数对旋翼气动特性的控制进行了分析研究。为克服变形网格方法可能导致网格畸变的不足，发展了一套适用于前飞状态带后缘小翼旋翼的运动嵌套网格方法。基于非定常雷诺平均Navier-Stokes（URANS）方程、k-ω剪切应力输运（SST）湍流模型和Roe-MUSCL插值格式，采用含LU-SGS隐式推进的双时间方法及并行技术，建立了一套适用于带有后缘小翼控制的旋翼前飞非定常流动特性模拟的高效CFD方法。以带后缘小翼的SMART旋翼为算例，对比了桨叶剖面等效法向力的计算结果，验证了CFD方法的有效性。着重开展了前飞状态旋翼后缘小翼的控制分析，在操纵量不变的情况下，分别研究了后缘小翼偏转幅值、偏转频率、安装位置及宽度等参数对旋翼气动力的影响特性，获得了典型参数对旋翼气动特性的控制规律。进一步研究了配平状态下后缘小翼对旋翼气动特性的参数影响。结果表明：后缘小翼可以充分发挥旋翼在前行侧的升力潜能，同时降低后行侧动态失速过程中旋翼的阻力和扭矩；在相同的旋翼拉力情况下，通过安装后缘小翼可以将旋翼阻力系数和扭矩系数分别降低17%和29%，升阻比提高14%。

Control mechanism and parameter analyses of aerodynamic characteristics of rotor via trailing-edge flap

Control effects of typical motion parameters of Trailing-Edge Flap (TEF) on the dynamic stall characteristics of the rotor are investigated. To overcome the shortcoming of the deformable grid approach, which may result in distortion of grid, a moving-embedded grid method is developed to predict the flowfield of the rotor with TEF control in the forward flight. Based on Unsteady Reynolds Averaged Navier-Stokes (URANS) equations, k-ω Shear Stress Transport (SST)turbulence model, Roe-MUSCL scheme, implicit LU-SGS scheme, parallel techniques and dual-time method, a high-efficiency CFD method is developed to predict the unsteady aerodynamic characteristics of rotor with TEF control. A comparison of calculation and experiment results of the normal force of the forward flight of the SMART rotor with TEF demonstrates validity of the proposed CFD method. Control effects of the forward flight of the rotor via trailing-edge flap are analyzed. Effects of the parameters including the angular amplitude, non-dimensional frequency, location and width of the trailing-edge flap on the aerodynamic characteristics of the rotor are explored with the same maneuvering. Parametric analyses of rotor aerodynamic characteristics are further investigated in the trimming condition. The results indicate that with TEF, rotors can reach their full lift potential in the advancing side, and the drag and torque of the rotor caused by dynamic stall in retreating blades can be reduced. With the same rotor thrust, the drag and torque coefficients of the rotor can be reduced by about 17% and 29% respectively control and the lift-to-drag ratio is increased by 14% via TEF.