Oblique tunnel portal effects on train and tunnel aerodynamics based on moving model tests

Zhang, Lei; Yang, Mingzhi; Liang, Xifeng; Zhang, Jian

doi:10.1016/j.jweia.2017.04.018

Cited by 88 publications

(27 citation statements)

References 35 publications

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“…Johnson and Dalley have conducted 1/25 th scaled experiments for a passenger train passing through a tunnel at the TRAIN RIG, and the comparison of pressures inside the tunnel with full scale results showed excellent agreement. 29 Similar experiments to the current study have been successfully performed recently by Zhang et al 30 using a scaled moving model. The pressure amplitudes do not change in full scale, but the pressure traces in the scaled tunnel occur 25 times faster than in full scale.…”

Section: Similarity Criteriasupporting

confidence: 76%

Experimental investigation of the aerodynamics of a freight train passing through a tunnel using a moving model

Iliadis

Soper

Baker

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part F:

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The objective of this study was to investigate the aerodynamic effects of a freight train passing through a tunnel. The nose entry generates a complex pattern of reflective pressure waves (piston effect) which can lead to intense aerodynamic forces. Previous research on the topic has focused on passenger trains because of higher speeds. The experiments of this study use a 1/25th scaled moving model at the TRAIN Rig at a speed of 33.5 m/s with a blockage ratio of 0.202. The monitored pressure along the tunnel wall can increase up to almost 1000 Pa because of the initial compression wave, while it drops when an expansion wave or the tail passes by. The maximum pressure is observed at the train nose due to air stagnation (1500 Pa) where the flow is steady, while the roof and sides experience negative pressures due to unsteady flow separation. The effect of loading configuration is significant as partially loaded trains can create a second pressure peak on the tunnel walls (after the initial compression wave) and affect the flow at the tunnel entrance wall. Under the current testing conditions, the results indicated compliance with the requirements of the Technical Specification for Interoperability and a constant pressure gradient of the initial compression wave which is in contrast with the passenger train's two-part gradient. Further work on the topic could provide visual information about the exiting jet towards the portal and the separation bubble around the train.

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Section: Similarity Criteriasupporting

confidence: 76%

Experimental investigation of the aerodynamics of a freight train passing through a tunnel using a moving model

Iliadis

Soper

Baker

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part F:

View full text Add to dashboard Cite

show abstract

“…(Chen et al, 2017;EN 14067-4. 2009) Thus, height of the domain should be no less than 10 times of the characteristic height (h) of the computational model, and the width of the domain should be no less than 20 times of the computational model (Chen et al, 2017;Zhang et al, 2017a).…”

Section: Boundary Conditionsmentioning

confidence: 99%

Aerodynamic Shape Design of Pantograph Network Monitoring Device on High-Speed Trains

Ji¹,

Wu²,

Qian³

et al. 2019

JAFM

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The pantograph monitoring device on high-speed trains bears not only its own strength but also the aerodynamic load applied by the air flow when the train is running at high speed. A well designed shape of the pantograph monitoring device on high-speed trains reduces the loads and pressure fluctuations acting on it, and therefore, increases its function stability and life cycle. In this paper, we present an aerodynamic shape design method for such device. Firstly, an efficient and reliable numerical simulation approach is established for the evaluation of the aerodynamic loads acting on the device. According to the numerical computations, a basic shape for the monitoring device is formed, with which the minimum functional space of the device is reserved. Then, the corners of the basic shape are smoothed out with three types of continuous transitions. By comparing the numerical results of the three smoothed shapes, we obtain an optimal aerodynamic shape for the pantograph monitoring device. The design method is not limited to the monitoring device studied in this manuscript. The aerodynamic shape of other small functional devices on high-speed trains can also be generated or optimized with the method presented herein.

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“…But the current level of hardware is far from being meet the demand of analyzing the effect of the coupled multi-parameters at the early stage of the produce design [9,10] . While, the one-dimensional, compressible, unsteady flow model [11,12,13,14] provide a theoretical basis for the rapid resolution of pressure wave in the railway tunnel.…”

Section: One-dimensional Flow Modelmentioning

confidence: 99%

“…g and a are gravity acceleration and speed of sound, respectively. w , G and q are work expression, friction term and heat transfer term [14] , respectively.…”

Section: Control Equationsmentioning

confidence: 99%

Numerical Investigation on Critical Tunnel Length of Maximum External Pressure Change of High-Speed Train

Jia¹,

Yuan-gui²

2017

dtetr

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This study describes the numerical investigations to estimate the critical tunnel length. A one-dimensional compressible unsteady non-homentropic flow model, and method of characteristics of generalized Riemann variables is adopted. Then, the critical tunnel length of 1) maximum positive pressure change, 2) maximum negative pressure change and 3) peak-peak pressure change is obtained. The difference between obtained critical tunnel length of maximum positive pressure change and maximum negative pressure change and that from formulas of EN 14067-5 and other scholar is investigated. The comparison shows that the critical tunnel length by our method is close to the formulas. In addition, the critical tunnel length of peak-peak pressure change which is more helpful to the fatigue design of train body and components is delivered. The method in this paper has been proved to be an efficient approach to obtain the critical tunnel length.

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Oblique tunnel portal effects on train and tunnel aerodynamics based on moving model tests

Cited by 88 publications

References 35 publications

Experimental investigation of the aerodynamics of a freight train passing through a tunnel using a moving model

Experimental investigation of the aerodynamics of a freight train passing through a tunnel using a moving model

Aerodynamic Shape Design of Pantograph Network Monitoring Device on High-Speed Trains

Numerical Investigation on Critical Tunnel Length of Maximum External Pressure Change of High-Speed Train

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