High-precision simulation of aeroelastic characteristics of TEF rotor based on CFD/CSD coupling

To analyze the aeroelasticity of Trailing Edge Flap (TEF) rotors in forward flight, a high-precision analysis method based on Computational Fluid Dynamics/Computational Structural Dynamics (CFD/CSD) coupling is established. A set of moving-embedded grid method for rotors with TEF is developed by the parametric method. In terms of aerodynamic analysis, the high-precision CFD method, based on the traditional aerodynamic model, is introduced to accurately simulate the unsteady flow field and aerodynamic characteristics of the rotor. In terms of structure, the dynamic model of rigid TEFs is established, the influence of the rigid TEF motion on the rotor system is considered in the form of additional mass, damping, stiffness and other matrices, and the nonlinear dynamic equation of the rotor system is derived based on Hamilton's principle and Timoshenko beam model. An elastic grid deformation method based on algebraic transformation is adopted, and the unsteady fluid-solid coupling strategy is developed. Results comparison of the aeroelastic loads of the model rotor and the SA349/2 rotor verifies the effectiveness of the CFD/CSD coupling method. On this basis, taking the SMART rotor with TEF as an example, the calculation results are compared with the equivalent normal force coefficient of the blade sections. Emphasis is placed on the analysis of the Fulton model rotor, studying the variation of blade root torque in hover and flap moment amplitude in forward flight, and comparing them with literature results. Results show that the proposed CFD/CSD coupling method can improve the analysis accuracy of the unsteady aeroelastic load of the rotor, and accurately capture the Blade-Vortex Interaction (BVI) phenomenon of the low-speed forward flight rotor, with the average error of flap bending moment controlled at 11.68%. Meanwhile, the natural frequency error of the blade with TEF is smaller than 4.0%, and the average error of flap bending moment amplitude of the blade root is 15.15%, meaning that the aeroelastic characteristics of the TEF can be effectively simulated. Under the single TEF control law, the hub vertical force F_z of the Fulton rotor can be effectively controlled, and the load amplitude is reduced by more than 80%.