Research on foreign particles splashing under high-speed train based on CFD-DEM coupling model

Foreign particle splashing induced by high-speed trains poses significant risks to underbody components due to aerodynamic forces. This study investigates gravel particle splashing mechanisms on ballastless tracks using a simulation model. The air domain is solved via Computational Fluid Dynamics, while particle dynamics are modeled using the Discrete Element Method. The sliding mesh technique simulates train-track relative motion, with aerodynamic forces acting directly on gravel particles. The results reveal that air pressure and velocity fluctuations subject particles to dual wind-induced loads. Train speed, particle velocity, and splashing height exhibit a nonlinear relationship. Particle movement varies by size/mass, with larger particles requiring higher speeds to splash. Based on these dynamics, particle size thresholds for splashing risks are proposed for different train speeds. This study provides practical insights into optimizing underbody protection design and ballast specifications to reduce particle splashing risks on high-speed railways.