Safety of a high-speed train passing by a windbreak breach under different wind speeds

2021 ◽  
pp. 095440972110460
Author(s):  
Zhuang Sun ◽  
Syeda Anam Hashmi ◽  
Huanyun Dai ◽  
Guiyu Li
Keyword(s):  
High Speed ◽  
Navier Stokes ◽  
Windward Side ◽  
High Speed Train ◽  
Wind Speeds ◽  
Pressure Fields ◽  
Body Dynamics ◽  
Multi Body ◽  
Yaw Angle ◽  
Moving Train

A derailment phenomenon could take place on the windward side of a 120 km/h high-speed train when it runs by a breach, between two windbreak walls, subjected to a normal wind speed of 32 m/s. To study the safety of a high-speed train under different normal speeds of crosswind, six wind speeds are investigated; 32 m/s, 28 m/s, 25 m/s, 20 m/s, 15 m/s, and 10 m/s. The wind forces and moments of the moving train are calculated using the Unsteady Reynolds-averaged Navier-Stokes (URANS) model, which are then applied to the train multi-body dynamics. The pressure fields around the train passing by the breach are analysed, which gives a reasonable explanation for the fluctuation of the wind loads. After an analysis on the response of the train, it is apparent that the risk of derailment on the windward side is much greater than the risk of overturning. The lateral distance of the first wheelset increases towards the windward side as along with the yaw angle of the wheelset, which increases as well with wind speeds of higher than 20 m/s.

scholarly journals Numerical Analysis and Characterization of Surface Pressure Fluctuations of High-Speed Trains Using Wavenumber–Frequency Analysis

2019 ◽  
Vol 9 (22) ◽  
pp. 4924
Author(s):  
Lee ◽  
Cheong ◽  
Kim ◽  
Kim
Keyword(s):  
Flow Field ◽  
Open Field ◽  
Frequency Analysis ◽  
Surface Pressure ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Interior Noise ◽  
High Speed Train ◽  
Pressure Fields ◽  
Time Space

The high-speed train interior noise induced by the exterior flow field is one of the critical issues for product developers to consider during design. The reliable numerical prediction of noise in a passenger cabin due to exterior flow requires the decomposition of surface pressure fluctuations into the hydrodynamic (incompressible) and the acoustic (compressible) components, as well as the accurate computation of the near aeroacoustic field, since the transmission characteristics of incompressible and compressible pressure waves through the wall panel of the cabin are quite different from each other. In this paper, a systematic numerical methodology is presented to obtain separate incompressible and compressible surface pressure fields in the wavenumber–frequency and space–time domains. First, large eddy simulation techniques were employed to predict the exterior flow field, including a highly-resolved acoustic near-field, around a high-speed train running at the speed of 300 km/h in an open field. Pressure fluctuations on the train surface were then decomposed into incompressible and compressible fluctuations using the wavenumber–frequency analysis. Finally, the separated incompressible and compressible surface pressure fields were obtained from the inverse Fourier transform of the wavenumber–frequency spectrum. The current method was illustratively applied to the high-speed train HEMU-430X running at a speed of 300 km/h in an open field. The results showed that the separate incompressible and compressible surface pressure fields in the time–space domain could be obtained together with the associated aerodynamic source mechanism. The power levels due to each pressure field were also estimated, and these can be directly used for interior noise prediction.

Simulation Analysis and Structure Optimum Design of the High Speed Conveying Manipulator Based on ADAMS

2014 ◽  
Vol 945-949 ◽  
pp. 121-126 ◽  
Author(s):  
Feng Wei Xue ◽  
Ji Ping Zhou
Keyword(s):  
Production Line ◽  
High Speed ◽  
Design Theory ◽  
Simulation Analysis ◽  
Structural Characteristics ◽  
Transmission System ◽  
Manufacturing Cost ◽  
Body Dynamics ◽  
Virtual Prototyping Technology ◽  
Multi Body

The conveying manipulator is an indispensable transmission system of JM31-160 automatic stamping production line, and structural characteristics of the manipulator directly affect the productivity of auto stamping production line. Using virtual prototyping technology, basing on the Multi-body dynamics theory, explored the technical line of dynamic design theory to apply on the transmission system. Reaching a conclusion the function of optimized structure is improved, and manufacturing cost brings down.

A numerical investigation on the improvement of anti-snow performance of the bogies of a high-speed train

2019 ◽  
Vol 234 (10) ◽  
pp. 1319-1334 ◽  
Author(s):  
Jiabin Wang ◽  
Yan Zhang ◽  
Jie Zhang ◽  
Xifeng Liang ◽  
Sinisa Krajnović ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
High Speed ◽  
Weather Conditions ◽  
Snow Accumulation ◽  
Navier Stokes ◽  
High Speed Train ◽  
Discrete Phase Model ◽  
Flow Features ◽  
High Speed Trains ◽  
Discrete Phase

In this paper, numerical simulations combining unsteady Reynolds-averaged Navier-Stokes (URANS) simulation and the discrete phase model are used to study the application of countermeasure for snow accumulation in the regions of bogie cavities of a high-speed train. The influence of the cowcatcher heights and guide structure configurations on the flow features and snow accumulation was studied. The results of the study show that the cowcatcher with a downward elongation of 4% of the distance between the two axles decreases the snow accumulation in the first and the second bogie regions by about 56.6% and 13.6%, respectively. Furthermore, the guide structures have been found to significantly alter the velocity and pressure distribution in the second bogie region, resulting in a relatively large snow-accumulation reduction. The deflector is found to perform better in reducing snow accumulation when compared to the diversion slots. The cowcatcher, elongated in the downward direction, and the deflector proved to be a good countermeasure for snow accumulation around the bogies of high-speed trains operating in snowy weather conditions.

Failure Effects of Anti-Hunting Damper on High-Speed Train

2013 ◽  
Vol 694-697 ◽  
pp. 90-94 ◽  
Author(s):  
Ji Min Zhang ◽  
Li Wen Man
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Critical Speed ◽  
Dynamic Performance ◽  
High Speed Train ◽  
Multi Body ◽  
Body Dynamic

The multi-body dynamic model of the high-speed train is established in order to study the failure effects of anti-hunting damper. Four kinds of failure case of the anti-hunting damper are compared, specifically including: one anti-hunting damper of the front bogie is broken; two anti-hunting dampers of the front bogie are broken; three anti-hunting dampers of the front bogie are broken; all four anti-hunting dampers of the front bogie are broken. The results have shown: when only one anti-hunting damper is broken, the influence to the dynamic performance of the high speed train is small, but once two anti-hunting dampers or more out of work, the critical speed of the vehicle decreases much more and the curve-passing performance also become worse.

Dynamic response of a high-speed train under a type of gust with different durations

2020 ◽  
pp. 095440972094784
Author(s):  
Zhuang Sun ◽  
Huanyun Dai ◽  
Feng Gan ◽  
Tingting Zhang ◽  
Hao Gao ◽  
...  
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Time Windows ◽  
Navier Stokes ◽  
High Speed Train ◽  
Root Locus ◽  
Scaling Factors ◽  
Natural Period ◽  
Derailment Coefficient ◽  
Locus Method

In order to study the effect of different gust durations on the safety of a high-speed train passing by a wind-break breach at a speed of 120 km/h, the root locus method is used to analyze the suspension modes of the train under different speeds. The original gust is obtained based on the Unsteady Reynolds-averaged Navier-Stokes (URANS) model when the train passes by a 12 m breach between two windbreaks with a normal crosswind speed of 32 m/s. A group of scaling factors for stretching and compressing the time windows is applied to change the gust duration without changing the amplitude. The results show that when the gust duration is close to the natural period of the suspension system, the train responses and derailment coefficient of the train can be amplified. As the attack angles of the first and second wheelset are still in the clockwise direction when overlooking the wheelset, the first wheelset is more vulnerable than the second wheelset. When the gust duration is longer than the natural period of lower sway, the initial fluctuation of the train response can be relieved.

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.

A Study of Aerodynamic Effects of High-Speed Trains through Tunnels

2011 ◽  
Vol 94-96 ◽  
pp. 1663-1667
Author(s):  
Jing Zhao ◽  
Ren Xian Li
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Navier Stokes ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
Geometry Model ◽  
Flow Geometry ◽  
High Speed Trains ◽  
Set Up ◽  
Numerical Calculation Method

In this paper, the aerodynamic effects of high-speed train passing in tunnels are investigated in numerical calculation method of hydromechanics. According to the actual situation of flow filed when the train through the tunnel, the flow geometry model is set up. The flow problem is described by Navier-Stokes equations of unsteady viscous compressible fluid and k-e two equations turbulent model. Thereby the aerodynamic effects of the train through the tunnel are analyzed comprehensively. The changes of the air pressure in tunnel caused by high-speed train entering into the tunnel are mainly analyzed. In addition, the mechanical characteristics of carriages when two train in the tunnel passing through each other are analyzed.

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