Abstract:
Dynamic stall is a complex, unsteady, and nonlinear aerodynamic phenomenon that widely exists in the operation of rotating mechanical equipment such as helicopters, wind turbines, and air compressors and in the high angle of attack maneuvers and formation flying of aircraft. This phenomenon involves flow separation, shear layer instability, and the generation and evolution of dynamic stall vortices. It is accompanied by significant aerodynamic hysteresis effects and dynamic load changes, which can easily lead to problems such as sudden drop in lift, sharp increase in drag, and flutter of the aircraft. Since cutting-edge aerodynamic problems such as unsteady transition prediction, high angle of attack separation, and reliable simulation of dynamic stall have not yet been solved, wind tunnel experiments have become the core means to reveal the characteristics and flow mechanisms of dynamic stall. This paper systematically reviews the essential attributes of dynamic stall and wind tunnel experimental methods, focusing on the research progress of pressure measurement, transition detection, and spatial flow field fine structure display and measurement technology. The study shows that high-precision and high-resolution experimental measurement technology is crucial to capturing the flow characteristics during dynamic stall, and error correction technology significantly improves the reliability of experimental results. In addition, future research needs further to strengthen the development of multi-physics field coupling measurement technology and combine intelligent wind tunnel experiments with machine learning methods to comprehensively analyze the flow mechanism of dynamic stall and provide efficient design optimization and flow control strategies for aerospace and wind energy fields.