基于PIV的有砟道床周围沙粒运动学特性研究OA

Sand intrusion into ballasted beds seriously threatens their long-term stability and operational safety.Based on wind tunnel experiments and particle image velocimetry(PIV),this study investigated the movement of sand particles around ballasted beds in a wind-sand environment by systematically measuring and analyzing the spatiotemporal evolution of particle velocity fields,directional distributions,and flux transport.The results show that,when the wind-sand flow passes through the ballast-rail system,the flow field structure changes significantly,exhibiting clear velocity stratification and flow direction reorganization.The particle motion direction undergoes a typical evolution process of convergence,deflection,chaos,and recovery along the flow path.The directional concentration decreases from 0.959 on the windward side to 0.200 in the inter-rail region,and then rises to 0.639 on the leeward side.The particle flux attenuates by about 48%along the path,while near-surface deposition is significant,with the proportion of downward-moving particles generally exceeding 60%at all measurement positions.The ballasted bed affects wind-sand transport through the combined mechanisms of energy dissipation and screening:energy dissipation continuously weakens the sand-carrying capacity of the airflow,while the screening effect promotes sand deposition within the ballast layer.