Study of the Aerodynamics of a High-Speed Train Motion Under Crosswind Effect

Document Type : Original Article

Authors

4th Year, Mech. Power Eng. Dept., Faculty of Engineering, Zagazig University, Zagazig 44519, Egypt.

10.21608/iugrc.2022.302520

Abstract

Modern high-speed trains' increasing velocity and decreased mass raise the topic of how severe cross winds may affect their aerodynamics. High-speed trains' running stability may be impacted by strong crosswinds due to the magnified aerodynamic forces and moments. The study of train aerodynamics under the effect of crosswind is growing with the help of various types of numerical simulation and wind tunnel. This study involved performing simulations of turbulent cross wind flows over the four cars of two simplified different models of high-speed trains at different angles of attack and different yaw angles accordingly. The train aerodynamic issues are closely associated with the flows occurring around train. The flow around the train has been considered as incompressible and was obtained by solving the incompressible form of the unsteady Reynolds-Averaged Navier-Stokes (RANS) equations combined with the SST K-ω turbulence model. Important aerodynamic coefficients such as the drag force, side force, and rolling moment coefficients have been calculated for angles of attack (0°,30°,45°,60°,90°). The results illustrated the formation of a large vortex upon the leeward side at yaw angle of 10° and above, this caused a region of low pressure which increased the overturning forces acting upon the train. Generally, crosswinds increased pressures upon the windward side of the train and decreased them upon the leeward side. Slipstream velocities on the windward side were seen to decrease whilst leeward side velocities increased. The Effect of the train shape and velocity on aerodynamic characteristics has been illustrated by comparing the results of the different cases of this study. The dependence of the flow structure on yaw angle has also been presented.

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