Effects of yaw angle on the unsteady aerodynamic performance of the pantograph of a high-speed train under crosswind

Abstract

In this study, the delayed detached eddy simulation approach based on the shear-stress transport κ-ω turbulent model was performed to simulate the unsteady aerodynamic performance of the pantograph of a high-speed train using yaw angles of 0°, 10°, 20°, and 30° with crosswind to determine how the yaw angle influenced the numerical simulation results. For validation, the simulation results were compared with wind tunnel test results, demonstrating good agreement. Additionally, the aerodynamic forces and instantaneous and time-averaged flow fields around the pantograph were analyzed. With increasing yaw angle, the flow field asymmetry and vortex intensity near the pantograph increased, the wake flow became more turbulent, and the unsteady aerodynamic characteristics became more obvious. Thus, the yaw angle affected the velocity field distribution near the pantograph considerably, especially in the wake flow area. The aerodynamic forces on the pantograph were also computed, and their time histories were used to reveal the characteristic frequencies of the flow motion around the pantograph. The time-averaged aerodynamic coefficients and their fluctuations increased with increasing yaw angle. In addition, the power spectral densities of the aerodynamic coefficients exhibited obvious peaks, while the aerodynamic coefficient frequency band was wider with crosswind than without crosswind.