Wind turbine is a rotating mechanical device that converts wind energy in the atmospheric boundary layer into electrical energy. It faces aerodynamic problems such as diversity of incoming flow conditions, complexity of flow around blades, and aeroelastic coupling. The aerodynamic characteristics of wind turbine directly determine its wind energy utilization efficiency and aerodynamic load, which is one of the grand challenges in the science of wind energy. Aerodynamic theory usually contains three levels: the pressure level characterized by velocity and pressure, the structure level characterized by vorticity and pressure gradient, and the causal level characterized by vorticity gradient. The former is difficult to reveal the physical source of the aerodynamic force; the middle has extremely high requirements on the accuracy of the flow field data; the latter can not only describe the quantitative contribution of the flow structure to the aerodynamic force, but also relax the accuracy requirements for the flow field data, so it becomes the mainstream and hot spots of aerodynamic theories. This project will investigate the structure level of wind turbine aerodynamics theories. The relevant results will be of great significance to wind energy applications, aerospace, fluid machinery and many other application fields.