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.

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.

Sensitivity Analysis of the Rectangular Trenches Employed in Suppression of the High-Speed Train-Induced Ground Vibrations

2010 ◽  
Author(s):  
Davood Younesian ◽  
Mehran Sadri
Keyword(s):  
High Speed ◽  
Vibration Reduction ◽  
Moving Loads ◽  
High Speed Train ◽  
Ground Vibrations ◽  
Infinite Domain ◽  
Aspect Ratios ◽  
Different Types ◽  
High Speed Trains ◽  
Train Speed

Ground vibrations generated by high-speed trains are studied in this paper. Open trenches are included in modeling and the problem is formulated using elasticity theory. The ground is modeled by a semi-infinite domain and the embankment with finite layers and the high-speed train is simulated by moving loads. The analytical solution is obtained in frequency domain and the peak particle velocity (PPT) is then achieved for different types of open trenches with different aspect ratios and distance from the track centerline. A parametric study is then carried out and effects of different parameters including the train speed and ground properties on vibration reduction factors are investigated.

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.

Iterative learning control of air pressure variation inside a high-speed train under the excitation of the tunnel pressure wave with a fixed-morphologic form

2021 ◽  
pp. 095440972110327
Author(s):  
Zhiying He ◽  
Chunjun Chen ◽  
Dongwei Wang ◽  
Chao Deng ◽  
Jia Hu ◽  
...  
Keyword(s):  
Iterative Learning Control ◽  
Pressure Wave ◽  
High Speed ◽  
Learning Control ◽  
Pressure Variation ◽  
Iterative Learning ◽  
Air Pressure ◽  
High Speed Train ◽  
Comfort Index ◽  
Simulation Signal

Based on the characteristics that the tunnel pressure wave has a fixed-morphologic form when the same train passes through the same tunnel, an applicational approach based on the iterative learning control (ILC) is developed, aiming at overcoming the drawbacks of the traditional strategy for controlling the air pressure variation inside a high-speed train carriage. To achieve the goal, the control system is mathematically modelled. Then, the problem is formulated. The task of suppressing the influence of the tunnel pressure wave on the air pressure inside the carriages is shifted as an ILC problem of tracking the comfort index with varying trial length. The algorithm of refreshing the control signal from trial to trial is determined and the process of ILC control is designed. Next, the convergence of the newly-developed applicational ILC algorithm is discussed and the algorithm is simulated by the simulation signal and field-test signal. Results show that the applicational ILC algorithm be more adaptable in handling the control of the air pressure inside carriage under the excitation of varying-amplitude, varying-scale and varying-initial-states tunnel pressure wave. Meanwhile, the matching with tunnel pressure wave makes the applicational ILC algorithm will take both the riding comfort and fresh air into consideration, which upgrades the performances when the high-speed train passing through long tunnels.

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.

scholarly journals A Study on the Energy-Harvesting Device with a Magnetic Spring for Improved Durability in High-Speed Trains

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 830
Author(s):  
Jaehoon Kim
Keyword(s):  
Energy Harvesting ◽  
High Speed ◽  
Permanent Magnets ◽  
Critical Issue ◽  
Sensor Nodes ◽  
High Speed Train ◽  
Vibration Energy Harvesting ◽  
Magnetic Spring ◽  
High Speed Trains ◽  
Energy Harvesting Devices

Durability is a critical issue concerning energy-harvesting devices. Despite the energy-harvesting device’s excellent performance, moving components, such as the metal spring, can be damaged during operation. To solve the durability problem of the metal spring in a vibration-energy-harvesting (VEH) device, this study applied a non-contact magnetic spring to a VEH device using the repulsive force of permanent magnets. A laboratory experiment was conducted to determine the potential energy-harvesting power using the magnetic spring VEH device. In addition, the characteristics of the generated power were studied using the magnetic spring VEH device in a high-speed train traveling at 300 km/h. Through the high-speed train experiment, the power generated by both the metal spring VEH device and magnetic spring VEH device was measured, and the performance characteristics required for a power source for wireless sensor nodes in high-speed trains are discussed.

The Aerodynamic Characteristics of the Pantograph When the Train Passes Through the Tunnel

2017 ◽  
Author(s):  
Dilong Guo ◽  
Wen Liu ◽  
Junhao Song ◽  
Ye Zhang ◽  
Guowei Yang
Keyword(s):  
High Speed ◽  
Aerodynamic Force ◽  
Maximum Amplitude ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Expansion Waves ◽  
Compression And Expansion ◽  
High Speed Trains ◽  
Current Characteristics ◽  
Pass Through

The aerodynamic force acting on the pantograph by the airflow is obviously unsteady and has a certain vibration frequency and amplitude, while the high-speed train passes through the tunnel. In addition to the unsteady behavior in the open-air operation, the compressive and expansion waves in the tunnel will be generated due to the influence of the blocking ratio. The propagation of the compression and expansion waves in the tunnel will affect the pantograph pressure distribution and cause the pantograph stress state to change significantly, which affects the current characteristics of the pantograph. In this paper, the aerodynamic force of the pantograph is studied with the method of the IDDES combined with overset grid technique when high speed train passes through the tunnel. The results show that the aerodynamic force of the pantograph is subjected to violent oscillations when the pantograph passes through the tunnel, especially at the entrance of the tunnel, the exit of the tunnel and the expansion wave passing through the pantograph. The changes of the pantograph aerodynamic force can reach a maximum amplitude of 106%. When high-speed trains pass through tunnels at different speeds, the aerodynamic coefficients of the pantographs are roughly the same.

Nonlinear Vibration and Comfort Analysis of High-Speed Trains Moving Over Railway Bridges

Volume 2 ◽  
2004 ◽  
Author(s):  
M. H. Kargarnovin ◽  
D. Younesian ◽  
D. J. Thompson ◽  
C. J. C. Jones
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Beam Theory ◽  
Maximum Acceleration ◽  
Railway Bridges ◽  
Comfort Index ◽  
Power Spectral ◽  
High Speed Trains ◽  
Train Speed ◽  
Track Bridge

The ride comfort of high-speed trains passing over railway bridges is studied in this paper. The effects of some nonlinear parameters in a carriage-track-bridge system are investigated such as the load-stiffening characteristics of the rail-pad and the ballast, rubber elements in the primary and secondary suspensions systems. The influence of the track irregularity and train speed on two comfort indicators, namely Sperling’s comfort index and the maximum acceleration level, are also studied. Timoshenko beam theory is used for modelling the rail and bridge and two layers of parallel damped springs in conjunction with a layer of mass are used to model the rail-pads, sleepers and ballast. A randomly irregular vertical track profile is modelled, characterised by a power spectral density (PSD). The ‘roughness’ is generated for three classes of tracks. Nonlinear Hertz theory is used for modelling the wheel-rail contact.

scholarly journals Source Contribution Analysis for Exterior Noise of a High-Speed Train: Experiments and Simulations

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jie Zhang ◽  
Xinbiao Xiao ◽  
Dewei Wang ◽  
Yan Yang ◽  
Jing Fan
Keyword(s):  
High Speed ◽  
Noise Source ◽  
High Speed Train ◽  
Noise Sources ◽  
Sound Sources ◽  
Lower Region ◽  
Source Contribution ◽  
Array Measurements ◽  
Noise Characteristics ◽  
Train Speed

This paper presents a detailed investigation into the contributions of different sound sources to the exterior noise of a high-speed train both experimentally and by simulations. The in situ exterior noise measurements of the high-speed train, including pass-by noise and noise source identification, are carried out on a viaduct. Pass-by noise characteristics, noise source localizations, noise source contributions of different regions, and noise source vertical distributions are considered in the data analysis, and it is shown how they are affected by the train speed. An exterior noise simulation model of the high-speed train is established based on the method of ray acoustics, and the inputs come from the array measurements. The predicted results are generally in good agreement with the measurements. The results show that for the high-speed train investigated in this paper, the sources with the highest levels are located at bogie and pantograph regions. The contributions of the noise sources in the carbody region on the pass-by noise increase with an increasing distance, while those in the bogie and train head decrease. The source contribution rates of the bogie and the lower region decrease with increasing train speed, while those of the coach centre increase. At a distance of 25 m, the effect of the different sound sources control on the pass-by noise is analysed, namely, the lower region, bogie, coach centre, roof region, and pantograph. This study can provide a basis for exterior noise control of high-speed trains.

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