The effect of ground clearance on the aerodynamics of a generic high-speed train
Journal article, 2020

The influence of ground clearance on the flow around a simplified high-speed train is investigated in this paper. Four clearance heights are studied using IDDES. After a grid independence study, the results of the simulations are validated against experimental data present in the literature. It is found that the drag decreases when reducing the clearance gap from the baseline height to a possibly critical height, while drag remains constant when the clearance is lower than this critical height. The negative lift (downforce) increases with the decreasing of the clearance gap. The flow is particularly influenced by the gap height at the underbody and wake regions, where a lower underbody velocity and a higher wake velocity are observed with lower clearance down to case h2. Therefore, the different topologies of the wake are presented and described. Particular attention is paid to the description of the wake flow and to the position and the formation of the flow mixing region. Specifically, with decreasing clearance, the mix of the tail downwash and underbody flows happen earlier, and the core of the counter-rotating vortices in the wake tends to develop with an increasing height trend. Overall, aerodynamic performance and flow structure descriptions show positive and negative effects when decreasing gap clearances, which should be taken into account for new design strategies.

Ground clearance

Train aerodynamics

Underbody flow

IDDES

Author

Tianyun Dong

Central South University

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Guglielmo Minelli

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Jiabin Wang

Central South University

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Xifeng Liang

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Central South University

Sinisa Krajnovic

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Journal of Fluids and Structures

0889-9746 (ISSN) 1095-8622 (eISSN)

Vol. 95 102990

Subject Categories

Aerospace Engineering

Fluid Mechanics and Acoustics

Oceanography, Hydrology, Water Resources

DOI

10.1016/j.jfluidstructs.2020.102990

More information

Latest update

6/24/2020