Research on Effects of Tunnel Buffer Structures on the Aerodynamic Force of the Pantograph

Abstract The pantograph subjected to sudden changes of the airflow while a high-speed train passes through the entrance and the exit of tunnels and the aerodynamic force acted on the pantograph fluctuate significantly, which can result in bad influence to the current characteristics of the pantograph. Aimed at studying the effect of buffer structures on such issue, the aerodynamic force of pantograph while passing through a tunnel with buffer structures, including bell mouth hoods, oblique hoods, and constant cross section (with the same cross section area to main tunnel) hoods were simulated by utilizing CFD software. The object of this study is a full-scale CRH380A train model composed of three groups with the CED400 pantograph model. The IDDES turbulence model combined the technique of overset grid is adopted in the computation. The results indicate that both the aerodynamic drag and lift fluctuation of the pantograph are reduced at the entrance and the exit of a tunnel with the bell mouth or side opening buffer structures, especially at the exit of the tunnel, the amplitude of lift force fluctuation can decrease to a quarter of the value in condition of conventional tunnels, the oblique hoods buffering structure has no obvious alleviation effects on the aerodynamic force fluctuations.