# Numerical Simulation of Fluid-Structure Coupling for a Multi-Blade Vertical-Axis Wind Turbine
###### Abstract
As a result, computer simulation has emerged as an important development trend. With the continuous development of simulation, there has been a growing trend of using simulation software to analyze the aerodynamic performance of wind turbines. Many experts and scholars abroad have made certain progress in the study of aerodynamic characteristics of wind turbines using FLUENT software. Various analysis ideas and methods are also being continuously validated in practice. [PERSON] and [PERSON] et al. [16] conducted a detailed study using FLUENT software to investigate the external flow around a two-dimensional airfoil. They discussed the effects of factors such as the angle of attack of the airfoil, chord length, and thickness on the lift and drag coefficient; [PERSON] and [PERSON] [17] conducted simulations using a finite volume fluid-structure interaction algorithm to study rigid vertical-axis wind turbines (VAWTs). They explored the feasibility of flexible blade (or deformable) VAWTs. [PERSON] and [PERSON] [18] used aerodynamic and fluid-structure interaction (FSI) computational techniques to perform dynamic, fully coupled 3D FSI simulations (referred to as \"full-scale\" simulations) of wind turbines with the presence of nacelles and towers. [PERSON] [19] conducted a unidirectional fluid-structure interaction simulation analysis of vertical-axis wind turbine blades. The study investigated the variations in blade surface pressure, structural stress-strain, and displacement of monitoring points under different tip-speed ratios. The research aimed to analyze the main loads acting on the blades during the rotation of the wind turbine, as well as the stress-strain and displacement responses of the blades. [PERSON] [20] studied the numerical simulation methods for aerodynamic loads on a 6 MW H-type vertical-axis wind turbine in a turbulent wind field. The research also focused on the structural form and strength characteristics of H-type wind turbines. By establishing a three-dimensional flow field mesh model and a structural finite element model, the boundary conditions obtained from simulation analysis were used to perform one-way fluid-structure coupling under startup, rated, and extreme conditions, validating the structural strength of the wind rotor. [PERSON] [21] et al. simulated the aerodynamic characteristics of a combined vertical-axis wind turbine using numerical simulations and experimental validation. The research shows that the addition of a Savonius wind turbine increased the power output of the combined wind turbine at low wind speeds, improving its startup performance. However, when the wind speed exceeded 8 m/s, the power properties of the combined wind turbine started to decline. [PERSON] [22] et al. conducted a comparative study between uni-directional and bi-directional fluid-structural coupling models for a horizontal axis wind turbine by FSI. The FSI problem needs to solve the coupled equations between the fluid and the solid fields, which can now be achieved due to advancements in numerical computation methods and computer technology. The entire computational domain involves solving the Navier-Stokes (N-S) equations for fluid flow and the nonlinear structural dynamics equations [23; 24; 25]. Generally, an iterative approach is used, where the fluid and structural domains are solved separately, and a coupling iteration is performed at each time step until convergence is achieved before advancing forward. In engineering analysis and research, since various physical phenomena are interconnected, pure single-field problems do not exist. Therefore, solving and analyzing practical problems using a multi-field coupling approach often yields more accurate and realistic results with more evident practical implications. In this paper, the vertical-axis wind turbine with different blades is studied. Due to the limited thinness of the vertical turbine blades, long-term usage may lead to deformation and damage in weak areas of the blades.