Abstract
Analysis of the slipstream development around the high-speed trains in tunnels would provide references for assessing the transient gust loads on trackside workers and trackside furniture in tunnels. This paper focuses on the computational analysis of the slipstream caused by high-speed trains passing through double-track tunnels with a cross-sectional area of 100 m2. Three-dimensional unsteady compressible Reynolds-averaged Navier-Stokes equations and a realizable k-ε turbulence model were used to describe the airflow characteristics around a high-speed train in the tunnel. The moving boundary problem was treated using the sliding mesh technology. Three cases were simulated in this paper, including two tunnel lengths and two different configurations of the train. The train speed in these three cases was 250 km/h. The accuracy of the numerical method was validated by the experimental data from full-scale tests, and reasonable consistency was obtained. The results show that the flow field around the high-speed trains can be divided into three distinct regions: the region in front of the train nose, the annular region and the wake region. The slipstream development along the two sides of train is not in balance and offsets to the narrow side in the double-track tunnels. Due to the piston effect, the slipstream has a larger peak value in the tunnel than in open air. The tunnel length, train length and length ratio affect the slipstream velocities; in particular, the velocities increase with longer trains. Moreover, the propagation of pressure waves also induces the slipstream fluctuations: substantial velocity fluctuations mainly occur in front of the train, and weaken with the decrease in amplitude of the pressure wave.
Highlights
High-speed railways have undergone vigorous development in recent years
The results show that the flow field around the high-speed trains can be divided into three distinct regions: the region in front of the train nose, the annular region and the wake region
The present study aims to use the 3D unsteady compressible Reynolds-averaged Navier– Stokes equations (RANS) and realizable k-ε turbulent model to investigate the characteristics of the slipstream caused by a passing high-speed train in double-track tunnels
Summary
High-speed railways have undergone vigorous development in recent years. The geographical setting and requirements of the track regularity standard have resulted in a large number of tunnels. There are over 300 tunnels in the Shanghai-Kunming High-speed Railway of China, with a total length of about 480 km. Slipstream development around a high-speed train in a tunnel trackside infrastructure. When a train enters a tunnel at high speed, the air that originally occupies the tunnel space is pushed ahead and aside by the train nose, as well in open air. Because of the confinement of tunnel walls, the airflow in a tunnel is significantly different than that in open air
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