Numerical Simulation of Effect of Nose Shape on Tunnel Entry/Exit Wave Induced by a High-Speed Train Passing through a Tunnel

2011 ◽  
Vol 97-98 ◽  
pp. 712-715
Author(s):  
Jian Lin Xu ◽  
Yuan Gui Mei ◽  
Fan Yang ◽  
Xin Liu
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
High Speed Train ◽  
High Speed Trains ◽  
Nose Shape ◽  
Volume Method ◽  
Wave Induced ◽  
Tunnel Entrance

The air flow around the high-speed train passing through a tunnel is three dimensional, compressible and unsteady in nature. This paper carried out the numerical simulation of it and evaluated the effect of nose shapes of high-speed trains on tunnel entry/exit waves radiated directly from tunnel entrance or exit. The elliptical, parabolic and conical nose shapes were analyzed. A commercial CFD code STAR-CD based on the finite volume method was used applying the SIMPLE algorithm and a moving grid technology. The comparison study shows that though the patterns of tunnel entry waves or exit waves induced by high-speed trains with above three nose shapes are similar, the amplitudes of them are different. The wave amplitude of elliptical shape is the highest, and that of conical shape is the lowest, which implies that with the nose shape be more streamlined and slender, it might be more likely to reduce the amplitudes of tunnel entry/exit waves.

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.

Analysis of Dynamic Wind of Sound Barrier under High Speed Train

2013 ◽  
Vol 361-363 ◽  
pp. 1536-1542
Author(s):  
Zhou Shi ◽  
Jun Li Guo ◽  
Wei Feng Su ◽  
Shuang Yang Zhang
Keyword(s):  
High Speed ◽  
Measured Data ◽  
Air Pressure ◽  
Turbulent Model ◽  
High Speed Train ◽  
Sound Barrier ◽  
Barrier Region ◽  
High Speed Trains ◽  
Train Speed ◽  
Volume Method

The special dynamic pulsating air pressure acting on the surface of sound barrier can be aroused by passing high speed train, making sound barrier structure and components prone to destruction and other issues. Based 3-D unsteady k-ε two-equation turbulent model, dynamic processes of high-speed trains passing the sound barrier region at different speeds and many factors are simulated and analyzed by using moving mesh finite volume method. The results of dynamic numerical calculated pulsating air pressure results and the effecting rule of various parameters were obtained, and compared with the measured data. It is showed that the air pressure value increases with the increasing train speed and the dynamic numerical calculated pulsating air pressure curves shape and effecting rule of parameters are all well matched with the measured data, but the air pressure value is slightly larger. At last, based on the results of numerical calculation, the addition of static air pressure value caused by high speed train is put forward.

Aerodynamic Comfort Analysis of High-Speed Trains Passing each other at the same Speed through a Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 2147-2151
Author(s):  
Ya Guang Yan ◽  
Qing Shan Yang ◽  
Jian Zhang
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Pressure Change ◽  
Unsteady State ◽  
Transient Pressure ◽  
Tunnel Length ◽  
Simulation Calculation ◽  
Aerodynamic Effect ◽  
High Speed Trains ◽  
Volume Method

On the basis of the three-dimensional,compressible,unsteady-state,viscous N-S Equation and k-ε turbulence model,the simulation calculation is made with the finite volume method on the aerodynamic effect of two high-speed trains passing each other at the same speed through a tunnel,simulating the pressure change,analysising regularity of the pressure,researching comfort in the train.The following conclusions have been drawn from research:The maximum of transient pressure is concerned with the meeting point,when the two high-speed trains meet in tunnel.When the length,the speed and the sealing factor of the train are same,the transient pressure is maximum with the trains meeting at the midpoint of tunnel.When the tunnel length,the speed of the train,the sealing factor and the point of meeting are same,the transient pressure of the longer train is maximum.When the sealing factor is greater than 15s,the standard of permissible pressure (1250Pa\3s) can be satisfied with all circumstances.

Aerodynamic Simulation of the Air Flow beneath the High Speed Train

2012 ◽  
Vol 253-255 ◽  
pp. 2035-2040
Author(s):  
Ye Bo Liu ◽  
Zhi Ming Liu
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Air Flow ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Navier Stokes ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
High Speed Trains

Numerical simulations were carried out to investigate the air flow and pressure distributions beneath high speed trains, based on the three-dimensional Reynolds-averaged Navier-Stokes equations with the SST k-ω two-equation turbulence model. The simulation scenarios were of the high speed train, the CRH2, running in the open air at four different speeds: 200km/h, 250km/h, 300km/h and 350km/h. The results show that, the highest area of pressure is located at the front underbody part of the train whist the pressure for rest of the train is relatively small. Increasing speed does not visibly increase the pressure coefficient, indicating that the pressure increases with the square of the operational speed.

The Analysis of Flow Characteristics for the High-Speed Train with Strong Crosswind Using CFD

2011 ◽  
Vol 66-68 ◽  
pp. 850-854
Author(s):  
Yong Liu ◽  
Ning Ping Cao
Keyword(s):  
High Speed ◽  
Flow Characteristics ◽  
Grid Method ◽  
The Body ◽  
High Speed Train ◽  
Fluid Field ◽  
High Speed Trains ◽  
Computational Fluid Dynamics Cfd ◽  
Hybrid Grid ◽  
Volume Method

High-speed trains are easily got overturned in strong crosswind. This paper aims to analyze the fluid field of high-speed train under different distortion angles by using computational fluid dynamics (CFD), hybrid grid method and finite volume method. The results shows that the vortexes roll by the separated airflow are alternating occur and develop along the body from the top and bottom. It causes a strong affect to the lateral stability of the train.

Numerical Simulation of Aerodynamic Behaviors of High-Speed Trains Crossing

2012 ◽  
Vol 562-564 ◽  
pp. 1390-1393
Author(s):  
Yong Chang Zhang ◽  
Yu Gong Xu ◽  
Fang Qin ◽  
Rui Cao
Keyword(s):  
Numerical Simulation ◽  
Pressure Wave ◽  
High Speed ◽  
Value Change ◽  
High Speed Train ◽  
Operating Condition ◽  
Uniform Velocity ◽  
High Speed Trains ◽  
Calculation Results ◽  
Peak Value

A model of CRH2 high-speed train has been established and the aerodynamics process of moving high-speed trains has been numerically simulated by using moving gird technology of CFdesign, Two kinds of operating condition, both trains have uniform and un-uniform velocity, were considered to analyze the aerodynamics pressure on the surfaces of the train. Finally, according to the calculation results, regularity of how the position where the highest pressure wave was located and its peak value change with the velocity increasing is concluded.

Wind-Induced Response of ADSS during the Passage of High-Speed Train

2014 ◽  
Vol 590 ◽  
pp. 69-73
Author(s):  
Yu Wang ◽  
Qiang Gao ◽  
Hai Lin Wang
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Induced Response ◽  
Wind Flow ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
High Speed Trains

In this paper, the wind-induced response of the ADSS is analyzed when the high-speed trains pass by. The wind flow field of the high-speed train is simulated based on the three-dimensional Reynolds-averaged Navier–Stokes equations, combined with the k-ε turbulence model. The result is shown that the wind load acting on the ADSS is quite low and the stress of the line clamp increases a little.

Three-dimensional numerical simulation of wave-induced scour around a pile on a sloping beach

2021 ◽  
Vol 233 ◽  
pp. 109174
Author(s):  
Jinzhao Li ◽  
David R. Fuhrman ◽  
Xuan Kong ◽  
Mingxiao Xie ◽  
Yilin Yang
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Sloping Beach ◽  
Wave Induced

Comparative study on the use of acoustic emission and vibration analyses for the bearing fault diagnosis of high-speed trains

2021 ◽  
pp. 147592172110360
Author(s):  
Dongming Hou ◽  
Hongyuan Qi ◽  
Honglin Luo ◽  
Cuiping Wang ◽  
Jiangtian Yang
Keyword(s):  
Acoustic Emission ◽  
Fault Diagnosis ◽  
High Speed ◽  
High Speed Train ◽  
Signal Attenuation ◽  
Transmission Path ◽  
Bearing Fault Diagnosis ◽  
Operation Conditions ◽  
Fault Features ◽  
High Speed Trains

A wheel set bearing is an important supporting component of a high-speed train. Its quality and performance directly determine the overall safety of the train. Therefore, monitoring a wheel set bearing’s conditions for an early fault diagnosis is vital to ensure the safe operation of high-speed trains. However, the collected signals are often contaminated by environmental noise, transmission path, and signal attenuation because of the complexity of high-speed train systems and poor operation conditions, making it difficult to extract the early fault features of the wheel set bearing accurately. Vibration monitoring is most widely used for bearing fault diagnosis, with the acoustic emission (AE) technology emerging as a powerful tool. This article reports a comparison between vibration and AE technology in terms of their applicability for diagnosing naturally degraded wheel set bearings. In addition, a novel fault diagnosis method based on the optimized maximum second-order cyclostationarity blind deconvolution (CYCBD) and chirp Z-transform (CZT) is proposed to diagnose early composite fault defects in a wheel set bearing. The optimization CYCBD is adopted to enhance the fault-induced impact response and eliminate the interference of environmental noise, transmission path, and signal attenuation. CZT is used to improve the frequency resolution and match the fault features accurately under a limited data length condition. Moreover, the efficiency of the proposed method is verified by the simulated bearing signal and the real datasets. The results show that the proposed method is effective in the detection of wheel set bearing faults compared with the minimum entropy deconvolution (MED) and maximum correlated kurtosis deconvolution (MCKD) methods. This research is also the first to compare the effectiveness of applying AE and vibration technologies to diagnose a naturally degraded high-speed train bearing, particularly close to actual line operation conditions.

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