Aerodynamic Study of Two Opposing Moving Trains in a Tunnel Based on Different Nose Contours

Li, W. H.; Liu, Tian‐Hua; Zhang, J.; Chen, Z. W.; Chen, X. D.; Xie, Tai-Zhong

doi:10.18869/acadpub.jafm.73.242.27738

Cited by 17 publications

(3 citation statements)

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“…Due to the shape of the head car, various operating conditions and the high turbulence, the flow around the high-speed trains is complex. (Lu et al 2012;Zhang et al 2017;Li et al 2017). At present, the main research methods for the train aerodynamics include theoretical analysis, wind tunnel tests and numerical simulation (Li et al 2021).…”

Section: Introductionmentioning

confidence: 99%

On the Scale Size of the Aerodynamic Characteristics of a High-Speed Train

Chang

Qin

et al. 2022

JAFM

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In the wind tunnel test of trains, the scale size changes the Reynolds numbers of trains, which may affect the aerodynamic characteristics of the train. Based on computational fluid dynamics (CFD), numerical models of train aerodynamics with five different scale sizes are established. The five different scale sizes are λ=1/1, 1/2, 1/8, 1/16 and 1/25, respectively, and the aerodynamic characteristics of trains running in the open-air operating condition and crosswind operating condition with different scale sizes are numerically simulated. The results show that the pressure drag coefficients and pressure lift coefficients of the train tend to decrease with the decrease of the scale size. In the open-air operating condition, compared with the full-size train, the pressure drag coefficient of the 1/25 th scaled train is less by 14.4%, and the pressure lift coefficients of the head car, middle car and tail car change 16.1%, 46.6% and 12.3%, respectively. The scale size affects the velocity gradient near the train surface and the position of flow separation changes. The decrease of the scale size leads to the decrease of Reynolds numbers and the increase of viscous drag coefficient. When the scale size is 1/25, the viscous drag coefficient of the train is 0.186, which is 48.6% larger than the one of the full-size train.Compared with the open-air operating condition, the trend of the pressure drag coefficients and viscous drag coefficients is consistent except for the head car in crosswind operating condition when the scale size decreases. In the range of scale size λ between 1/1 and 1/25, the aerodynamic drag coefficient of the head car, middle car and tail car increase with the decrease of scale size, and the difference in the aerodynamic drag coefficient of the train is 12.9%. In addition, the train's aerodynamic lift coefficient shows an increasing trend with the decrease of scale size.

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Section: Introductionmentioning

confidence: 99%

On the Scale Size of the Aerodynamic Characteristics of a High-Speed Train

Chang

Qin

et al. 2022

JAFM

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“…These pressure waves will lead to drastic pressure fluctuations inside the tunnel, exerting an adverse impact on the tunnel facilities, and they therefore need to be reduced. 2 The pressure fluctuations may also access the interior cabins through the leakages, causing discomfort to passengers’ ears. 2–4…”

Section: Introductionmentioning

confidence: 99%

“…2 The pressure fluctuations may also access the interior cabins through the leakages, causing discomfort to passengers’ ears. 2–4…”

Section: Introductionmentioning

confidence: 99%

Parameter study and optimization design of a hat oblique tunnel portal

Guo

Liu

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part F:

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The present work focuses on the aerodynamic problems resulting from a high-speed train (HST) passing through a tunnel. Numerical simulations were employed to obtain the numerical results, and they were verified by a moving-model test. Two responses, [Formula: see text] (coefficient of the peak-to-peak pressure of a single fluctuation) and[Formula: see text] (pressure value of micro-pressure wave), were studied with regard to the three building parameters of the portal-hat buffer structure of the tunnel entrance and exit. The MOPSO (multi-objective particle swarm optimization) method was employed to solve the optimization problem in order to find the minimum [Formula: see text] and[Formula: see text]. Results showed that the effects of the three design parameters on [Formula: see text] were not monotonous, and the influences of[Formula: see text] (the oblique angle of the portal) and [Formula: see text] (the height of the hat structure) were more significant than that of[Formula: see text] (the angle between the vertical line of the portal and the hat). Monotonically decreasing responses were found in [Formula: see text] for [Formula: see text] and[Formula: see text]. The Pareto front of [Formula: see text] and[Formula: see text]was obtained. The ideal single-objective optimums for each response located at the ends of the Pareto front had values of 1.0560 for [Formula: see text] and 101.8 Pa for[Formula: see text].

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