Overview of aerodynamic drag reduction optimization for high-speed trains

When operating, high-speed trains are subject to aerodynamic resistance, which significantly affects the aerodynamic performance of the trains, thereby impacting their speed and energy consumption. This paper studies the distribution and types of aerodynamic resistance of high-speed trains, describes the methods and cutting-edge measures for reducing aerodynamic resistance, and presents the research on aerodynamic drag reduction. The aerodynamic resistance of high-speed trains is mainly distributed in the train's head, pantograph, bogie system, and exposed parts of the train's exterior. The main body of the train accounts for approximately 60.6% of the aerodynamic resistance, while the bogie system accounts for approximately 27.4%. Reducing aerodynamic resistance can be achieved by installing skirts and deflector covers on the bogie structure, smoothing the main body of the train, and adding deflector covers to exposed parts of the train, such as the pantograph system and air conditioning. This will reduce the impact of aerodynamic resistance on the aerodynamic performance of high-speed trains. The methods for reducing aerodynamic resistance are mainly divided into numerical simulation and wind tunnel experiments. Numerical simulation has low cost but requires experimental verification for accuracy, while experimental cost is high and is limited by the size of the model. Therefore, the combined research approach of the two is superior. The current cutting-edge methods for reducing aerodynamic resistance mainly include active control and passive control. Active control is operated through methods such as suction and blowing air, plasma jet, etc., while passive control is achieved by changing the surface and shape of the train, such as introducing biomimetic microstructures. In the future, active control will be further developed on the basis of combining the two to promote the high-level and high-quality development of high-speed trains.