Moving model analysis on the transient pressure and slipstream caused by a metro train passing through a tunnel

Meng, Shuang; Zhou, Dan; Wang, Zhe

doi:10.1371/journal.pone.0222151

Cited by 33 publications

(7 citation statements)

References 35 publications

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“…Studies of aerodynamic effects occurring while trains are passing through tunnels are widely covered in recent publications. Scientists investigate the aerodynamic performance of a high-speed train in a tunnel involving fullscale experiments, scale modelling tests, and numerical simulations [6][7][8]. Herein, particular attention is given to aerodynamic pressure effects resulting from the increasing speed of high-speed trains as the generated pressure fluctuations affect heavily the safety of a train body and tunnel facilities and cause damages [9,10].…”

Section: Introductionmentioning

confidence: 99%

Research@ZaB: Study of FDS Capabilities to Assess the High-Speed Train Impact on Pressure Pattern Within a Railway Tunnel

Patsekha

Galler

2021

Berg Huettenmaenn Monatsh

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The “wind tunnel” approach is applied to study high-speed train aerodynamics in a railway tunnel using FDS software. The main focus of the research is on the pressure distribution along the tunnel. Proven analytical dependencies based on the experimental observations for air jet centerline velocity and flow entrainment are used to evaluate the model setup. A model verification is carried out based on the pressure drop calculations due to viscous effects where the impact of the surface roughness and the tunnel length are also considered. A sensitivity analysis is performed to evaluate changes in input FDS parameters and to explore interactions between them. It is proposed to use the standard deviation, obtained from the calculated time-averaged pressure values, to specify the appropriate numeric parameter combinations, e.g. DT and PRESSURE_TOLERANCE, considering the desired results consistency and the computational time consumed. The simulated cases with and without a train inside a tunnel provide data on the aerodynamic characteristics of the models. The obtained volumetric and cross-sectional profiles for pressure and airflow velocity distribution form the basis for an informed decision regarding the tunnel design or safety solutions, for example, defining areas under maximal and minimal pressure loads. The analysis displays the necessity to carefully manage each investigated case considering the FDS features and limitations that largely affect a model setup and calculations.

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Section: Introductionmentioning

confidence: 99%

Research@ZaB: Study of FDS Capabilities to Assess the High-Speed Train Impact on Pressure Pattern Within a Railway Tunnel

Patsekha

Galler

2021

Berg Huettenmaenn Monatsh

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“…With the increase of the train speed, the requirements for high-speed railway lines and tunnels and other infrastructures are also constantly improving. Because the EMU trains are exposed to sound barriers, strong crosswinds, passing cars, and tunnels during operation, the condition affects the steady-state of the train, causing severe vibration of the body and affecting the comfort and safety of passengers [4,5].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Behaviour Analysis of Emu Train Entering and Exiting Tunnels Using Aerodynamic Load Data

2021

IJOMAM

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To study the change of aerodynamic load pressure when the EMU (Electric Multiple Unit) enters and exits the tunnel, the corresponding aerodynamic equation is established. By analysing the development process of EMU trains under mechatronics, a research background for the air pressure problem caused by the speed increase of high-speed trains is displayed. Furthermore, the aerodynamic problems and related pressure waves in the tunnel of the training group are introduced. Based on the aerodynamic load data, the lateral vibration characteristics of the train are analysed. It is proposed that after the train enters the tunnel, the surrounding air generates pressure waves and expansion waves due to the restriction of the train surface and the tunnel wall. Subsequently, the Bernoulli equation is used to calculate the pressure values of the train under different running conditions in the tunnel. Finally, the ANSYS Fluent fluid calculation software is used to simulate the aerodynamics of the train tunnel of the EMU. The results show that, affected by space constraints and air compressibility, when the train enters the tunnel, the compression wave changes from three-dimensional to one-dimensional. After the head of the train enters the tunnel, the average pressure value at the cross-section of x=2D increases rapidly. At t=0.011 second, the average pressure of the cross-section increases slowly, and the rate of change reaches the maximum. At t=0.027 second, the average pressure of the cross-section reaches the maximum. When the train approaches the cross-section, the pressure value at the sampling point close to the train body changes much greater than the change rate of the other two sampling points. The simulation results show that the transverse force of the train in the tunnel is 0.45Kn. Therefore, when the train travels in the tunnel, it will be subject to more complicated aerodynamic load conditions. This study will provide references for studying the aerodynamics of high-speed trains passing through tunnels.

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“…However, higher running speed of HSTs results in larger energy costs, mainly due to a relevant aerodynamic drag increase. 1,2 For the improvement of train aerodynamic performance, many studies have been conducted based on different techniques, such as full-scale tests, 3 moving model tests, 4,5 wind tunnel tests, 6,7 and numerical simulations. 8–10 Most of the research in this field focuses on the improvement of the shape of the streamlined parts of trains, 10–12 on the optimization pantographs shapes, 13 or inter-carriage gap structures.…”

Section: Introductionmentioning

confidence: 99%

An improved delayed detached eddy simulation study of the bogie cavity length effects on the aerodynamic performance of a high-speed train

Wang

Minelli

Zhang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper uses an improved delayed detached eddy simulation method to investigate the unsteady flow features of the high-speed trains with various cavity lengths at Re = 1.85×106. The improved delayed detached eddy simulation results are validated against the experimental data obtained during previous wind tunnel tests. The effects of cavity length on the resistance force, flow structures beneath the high-speed train and in the wake are analyzed. The results show that a longer cavity significantly increases the streamwise velocity level near the rear plates and forms a stronger impinging flow on the rear plates, and thus contributes to a higher value of resistance. Furthermore, a longer cavity decreases the pressure coefficients around the near wake region from the top of the ballast to the tail nose in the vertical direction and thereby increases the pressure drag of the high-speed train. Additionally, a longer bogie cavity is found to increase the longitudinal vortex scales in the near wake region. All these changes on the flow field bring to 5.8% and 11.5% drag increase when the bogie cavities are elongated by 20% and 40%, respectively, of the wheelbase.

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Moving model analysis on the transient pressure and slipstream caused by a metro train passing through a tunnel

Cited by 33 publications

References 35 publications

Research@ZaB: Study of FDS Capabilities to Assess the High-Speed Train Impact on Pressure Pattern Within a Railway Tunnel

Research@ZaB: Study of FDS Capabilities to Assess the High-Speed Train Impact on Pressure Pattern Within a Railway Tunnel

Dynamic Behaviour Analysis of Emu Train Entering and Exiting Tunnels Using Aerodynamic Load Data

An improved delayed detached eddy simulation study of the bogie cavity length effects on the aerodynamic performance of a high-speed train

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