Numerical simulation of slipstreams and wake flows of trains with different nose lengths passing through a tunnel
Journal article, 2021

This study examined the slipstreams induced by high-speed trains (HSTs) passing through a tunnel using the improved delayed detached eddy simulation (IDDES) method. First, the flow fields in the open air and in a tunnel were compared. Furthermore, the flow in a tunnel was analyzed in detail, considering the development of both instantaneous flow structures and slipstream profiles at various measurement points. Finally, by considering four different nose lengths (4 m, 7 m, 9 m, and 12 m), the differences in the slipstream profiles and the wake flow induced by HSTs passing through a tunnel were determined. The results show that the piston effect had a significant influence on the slipstream profiles, causing a larger positive peak when a train passed through a tunnel. The peaks of the slipstream profiles decrease as the distances from the center of the track (COT) and the top of the rail (TOR) increases. The results show that a long nose length can reduce the scale and strength of the instantaneous x-vorticity and y-vorticity in the wake propagation region, thereby lowering the maximum slipstream peaks. The 12-m nose length train induced 56.7% lower velocity than the 4-m nose length train at y = 2 m beside the COT and z = 0.2 m above the TOR. In particular, the standard deviations of the positive peaks of the seven cross-sections decrease by 38.4% with the increase in the nose length from 4 m to 12 m, which means that a longer nose length can reduce the turbulence level in the wake propagation region. Consequently, from the perspectives of the safety and comfort of trackside people, a long nose length train is strongly recommended.

Wake flow

Railway tunnel

Train nose length

High-speed train

Slipstream

Author

Shuang Meng

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

Central South University

Joint International Research Laboratory of Key Technology for Rail Traffic Safety

Xianli Li

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

Central South University

Joint International Research Laboratory of Key Technology for Rail Traffic Safety

Guang Chen

Joint International Research Laboratory of Key Technology for Rail Traffic Safety

Central South University

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

Dan Zhou

Central South University

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

Joint International Research Laboratory of Key Technology for Rail Traffic Safety

Zheng wei Chen

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

Central South University

Joint International Research Laboratory of Key Technology for Rail Traffic Safety

Sinisa Krajnovic

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Tunnelling and Underground Space Technology

0886-7798 (ISSN)

Vol. 108 103701

Subject Categories

Vehicle Engineering

Fluid Mechanics and Acoustics

DOI

10.1016/j.tust.2020.103701

More information

Latest update

1/7/2021 1