Propagation characteristic estimations of 2 GHz inter-car wireless links in high-speed train cars in a railway tunnel

2014 ◽  
Author(s):  
Masami Shirafune ◽  
Takashi Hikage ◽  
Toshio Nojima ◽  
Motoharu Sasaki ◽  
Wataru Yamada ◽  
...  
Keyword(s):  
High Speed ◽  
Propagation Characteristic ◽  
High Speed Train ◽  
Railway Tunnel ◽  
Wireless Links

scholarly journals Influences of High-Speed Train Speed on Tunnel Aerodynamic Pressures

2021 ◽  
Vol 12 (1) ◽  
pp. 303
Author(s):  
Jianming Du ◽  
Qian Fang ◽  
Jun Wang ◽  
Gan Wang
Keyword(s):  
High Speed ◽  
Peak Pressure ◽  
Stage I ◽  
Stage Ii ◽  
Stage Iii ◽  
High Speed Train ◽  
Railway Tunnel ◽  
Maximum Peak ◽  
Train Speed ◽  
Three Stages

To comprehensively investigate the characteristics of aerodynamic pressures on a tunnel caused by the whole tunnel passage of a high-speed train at different speeds, we conduct a series of three-dimensional numerical simulations. Based on the field test results obtained by other researchers, the input parameters of our numerical simulation are determined. The process of a high-speed train travelling through a railway tunnel is divided into three stages according to the spatial relationship between the train and tunnel. Stage I: before train nose enters the entrance; Stage II: while the train body runs inside the tunnel; Stage III: after the train tail leaves the exit. The influences of high-speed train speed on the tunnel aerodynamic pressures of these three stages are systematically investigated. The results show that the maximum peak pressure value decreases with increasing distance from the entrance and increases with increasing train speed in Stage I. There is an approximately linear relationship between the three types of maximum peak pressure (positive peak, negative peak, and peak-to-peak pressures) and the power of the train speed in Stage II. These three types of maximum peak pressure values of the points near tunnel portals increase with increasing train speed in Stage III. Moreover, these three types of maximum peak pressure in the tunnel’s middle section at different train speeds are more complex than those near the tunnel portals, and there is one or more turning points due to the superimposed effects of different pressure waves.

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

2021 ◽  
Author(s):  
Aliaksei Patsekha ◽  
Robert Galler
Keyword(s):  
High Speed ◽  
Model Verification ◽  
Computational Time ◽  
High Speed Train ◽  
Tunnel Length ◽  
Railway Tunnel ◽  
Air Jet ◽  
Tunnel Design ◽  
Model Setup ◽  
The Impact

AbstractThe “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.

Three Dimensional Numerical Simulation Study on Lining Pressure of High-Speed Railway Tunnel

2011 ◽  
Vol 243-249 ◽  
pp. 3670-3675
Author(s):  
Yun Dong Ma ◽  
Bo Li ◽  
Bin Fan
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Compressible Flows ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
High Speed Train ◽  
Railway Tunnel ◽  
Time Curve ◽  
High Speed Railway ◽  
Aerodynamic Effect

The aerodynamic numerical simulation model of high-speed railway tunnel was established based on the analyzing of the aerodynamic effect characteristics of high-speed railway tunnel. FLUENT three dimensional compressible flows SIMPLE algorithm was adopted, the three dimensional aerodynamic effect of high-speed railway tunnel was simulated on the condition that the high-speed train was in motion. The pressure changes law in the tunnel was obtained during the whole process when high-speed train traveling, and the pressure-time curve in the tunnel middle cross-section was plotted. It laid a foundation for the further development of tunnel lining dynamics analysis.

Propagation modeling for outdoor-to-indoor and indoor-to-indoor wireless links in high-speed train

Measurement ◽  
2017 ◽  
Vol 110 ◽  
pp. 43-52 ◽  
Author(s):  
Lei Zhang ◽  
José Rodríguez-Piñeiro ◽  
Jean R.O. Fernández ◽  
José A. García-Naya ◽  
David W. Matolak ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Train ◽  
Propagation Modeling ◽  
Wireless Links ◽  
Indoor Wireless

Single Opening Tunnel Hood Parameter Sensitive Research

2013 ◽  
Vol 353-356 ◽  
pp. 1759-1765
Author(s):  
Ying Xue Wang ◽  
Bo Gao ◽  
Yu Min Wen ◽  
Lun Gui Li
Keyword(s):  
Pressure Wave ◽  
High Speed ◽  
Simulation Method ◽  
High Speed Train ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Railway Line ◽  
Opening Ratio ◽  
Single Opening ◽  
Tunnel Entrance

when high-speed train passing through tunnel, the micro-pressure wave noise will be created at tunnel exit, which worsening the living environmental condition along the railway line. Building hood at tunnel entrance is an effective method for solving this problem. In this paper, using numeral simulation method, the efficiency of single opening tunnel hood relieving micro-pressure wave noise was researched, the sensitive of hood opening parameter, such as opening ratio, ratio of length and width, was analyzed. In the end, the tunnel hood optimizing parameters was drawn out, which will play an important guiding role for high-speed railway tunnel hood design.

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