## 1 Introduction  
In the past 20 years, with the emergence of global energy, environmental and resource problems, especially global warming and increasing depletion of fossil energy sources, it has become more and more obvious to vigorously develop renewable energy and accelerate the green and low-carbon transformation of the energy system, and wind energy has become a common choice for countries around the world to cope with climate change and ensure energy security [1]. With the increase in wind turbine blade size, the deformation of the blade is getting larger and larger, and the deformation of the blade has a greater impact on the local distribution of the flow field, aeroelasticity becomes an important part of the optimal design of the blade. The essence of the aeroelasticity problem is fluid-structure coupling, which can respond to the interaction between the structure and the aerodynamic forces on the structure in real time, thus more accurately describing the operating state and the real-time changes in power generation of wind turbines operating in a real environment. In the last decade, an increasing number of scholars have studied the aeroelasticity of wind turbine blades by various methods. First, for the model of fluid-solid coupling, scholars from various countries have studied different forms of coupling (unidirectional or bidirectional) for different objects. [PERSON] and [PERSON] and [PERSON] et al. (2011) [2] developed a new method for studying unidirectional fluid-structure coupling of VAWT blades. The effects of different fluid models, different time steps and different blade rotation angular velocities on aerodynamic performance of wind turbine blades were considered. [PERSON] et al. (2012) [3] carried out numerical simulation of centrifugal pump with unidirectional and bidirectional fluid-structure coupling methods, discussed the problem of solid vibration, and compared the analysis results with the experimental results. In the same year, [PERSON] used the modified strip theory (MST) to establish the aerodynamic model and structural model based on the multi-body dynamics method and realized the aeroelastic analysis of wind turbine blades. [PERSON] (2014) [4] applied software NUMECA and ABAQUS to numerically simulate the aeroelastic response and aerodynamic load of wind turbine rotor blades by using the CFD-CSD coupling method, calculated the aerodynamic load of blades based on the N-S equation, and calculated the elastic deformation of blades based on the CSD solver of FEM. [PERSON] (2016) [5] et al. realized the fluid-solid interaction between the structural part of HAWC2 aeroelastic solution and the finite-volume CFD solver EllipSys3D. Although only the weak coupling between the two was realized, sufficient numerical stability and second-order accuracy were maintained. The research on the aeroelasticity of large wind turbine blades focuses on rapid wake prediction and 3D modeling. In terms of rapid wake prediction and calculation, [PERSON] (2019) [6] calculated the aerodynamic performance of the floating fan by using the openFOAM with CFD toolbox and turbinesFOAM based on the elastic excitation line. The aerodynamic elasticity of the blade has little influence on the aerodynamic performance of the fan, especially in the wake field, which has almost no influence. For the analysis of three-dimensional models, especially the structural analysis, scholars from different countries have also adopted different software or programs to conduct relevant studies: [PERSON] (2016) [7] proposed that in blade modeling, three-dimensional finite element method has the highest calculation accuracy, but takes the longest time. [PERSON] et al. (2017) [8] developed an aeroelastic method for wind turbines, emphasizing the influence of aeroelasticity on aerodynamics and structural performance. [PERSON] et al. (2018) [9] proposed an aeroelastic model of wind turbine blade derived from the unsteady Navier-Stokes equations and a structural dynamics model based on modal shapes.