The Influence of Wind-Blown Sand on High-Speed Train Aerodynamic Performance

2016 ◽  
Author(s):  
T.T. Wang ◽  
C.W. Jiang ◽  
Z.X. Gao ◽  
C.H. Lee
Keyword(s):  
High Speed ◽  
Aerodynamic Performance ◽  
High Speed Train

Effect of bogie fairings on the flow behaviours and aerodynamic performance of a high-speed train

2019 ◽  
Vol 58 (6) ◽  
pp. 890-910 ◽  
Author(s):  
Jiabin Wang ◽  
Guangjun Gao ◽  
Xiaobai Li ◽  
Xifeng Liang ◽  
Jie Zhang
Keyword(s):  
High Speed ◽  
Aerodynamic Performance ◽  
High Speed Train

scholarly journals Complexity Analysis on the Aerodynamic Performance of the Mega High-Speed Train Caused by the Wind Barrier on the Embankment

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
He-xuan Hu ◽  
Wan-xin Lei ◽  
Ye Zhang
Keyword(s):  
Negative Pressure ◽  
High Speed ◽  
Complexity Analysis ◽  
Aerodynamic Force ◽  
Pressure Change ◽  
Aerodynamic Performance ◽  
Head Wave ◽  
High Speed Train ◽  
Aerodynamic Forces ◽  
Negative Wave

With the world development of high-speed railways and increasing speeds, aerodynamic forces and moments acting on trains have been increased further, making trains stay at a “floated” state. Under a strong crosswind, the aerodynamic performance of a train on the embankment is greatly deteriorated; lift force and horizontal force borne by trains will be increased quickly; trains may suffer derailing or overturning more easily compared with the flat ground; train derailing will take place when the case is serious. All of these phenomena have brought risks to people’s life and properties. Hence, the paper establishes an aerodynamic model about a high-speed train passing an air barrier, computes aerodynamic forces and moments, and analyzes pulsating pressures on the train surface as well as those of unsteady flow fields around the train. Computational results indicate that when the train passed the embankment air barrier, the head wave of air pressure full wave is more than the tail wave; the absolute value of negative wave is more than that of the positive wave, which is more obvious in the head train. When the train is passing the air barrier, pressure pulsation values at head train points are more than those at other points, while pressure changes most violently at the train bottom, and pressure values close to the air barrier are more than those points far from the air barrier. Pressure values at the cross section 1 were larger than those of other points. Pressure values at measurement points of the tail train ranked the second place, with the maximum negative pressure of 1253 Pa. Pressure change amplitudes and maximum negative pressure on the train surface are increased quickly, while pressure peak values on the high-speed train surface are in direct ratio to the running speed. With the increased speed of the high-speed train, when it is running in the embankment air barrier, the aerodynamic force and moment borne by each train body are increased sharply, while the head train suffers the most obvious influences of aerodynamic effects.

Numerical simulation of aerodynamic performance of a couple multiple units high-speed train

2017 ◽  
Vol 55 (5) ◽  
pp. 681-703 ◽  
Author(s):  
Ji-qiang Niu ◽  
Dan Zhou ◽  
Tang-hong Liu ◽  
Xi-feng Liang
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Aerodynamic Performance ◽  
High Speed Train ◽  
Multiple Units

scholarly journals Influence of Rectangular Strips’ Size on Aerodynamic Performance of a High-Speed Train Subjected to Crosswind

2021 ◽  
Author(s):  
Mengying Wang ◽  
Zhenxu Sun ◽  
Shengjun Ju ◽  
Guowei Yang
Keyword(s):  
High Speed ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Orthogonal Experimental Design ◽  
High Speed Train ◽  
Force Coefficient ◽  
Roll Moment ◽  
Side Force ◽  
Moment Coefficient ◽  
Side Force Coefficient

Abstract Conventional studies usually assume that the train surface is smooth, so as to simplify the numerical calculation. In fact, the surface of the train is irregular, which will change the flow characteristics in the boundary layer and further affect the aerodynamic performance of a train. In this work, roughness is applied to the roof of a 1:25 scaled train model in the form of longitudinal strips. Firstly, the improved delayed detached eddy simulation (IDDES) method is adopted to simulate the aerodynamic performance of the train model with both smooth and rough surface, which are subjected to crosswind. Results show that the side force coefficient and the roll moment coefficient subjected to rough model decreased by 3.71% and 10.56% compared with the smooth model. Then, the width, height and length of the strips are selected as variables to design different numerical simulation schemes based on the orthogonal experimental design method. Through variance analysis, it can be found that four design parameters have no significant effect on the side force coefficient. Meanwhile, for the roll moment coefficient, the length of the strips in the straight region of the train has a significant effect and the width of the strips has a highly significant effect on it. These conclusions can provide a theoretical basis to improve the aerodynamic performance of the high-speed train subjected to crosswind.

scholarly journals Primary Study of Aerodynamic Performance Evaluation and Optimization of the High-Speed Train

2011 ◽  
Author(s):  
X. P. Wang ◽  
K. Cui ◽  
S. C. Hu ◽  
T. Y. Gao ◽  
G. W. Yang ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
High Speed ◽  
Aerodynamic Performance ◽  
Primary Study ◽  
High Speed Train

Numerical and Experimental Investigation on Centrifugal Cooling Fan in a Traction Motor

2018 ◽  
Author(s):  
Xiaoyun Qu ◽  
Jie Tian ◽  
Tong Wang
Keyword(s):  
High Speed ◽  
Aerodynamic Performance ◽  
Aerodynamic Noise ◽  
Centrifugal Fan ◽  
High Speed Train ◽  
Traction Motor ◽  
Rotating Speed ◽  
Cooling Fan ◽  
Wide Range ◽  
Cfd Method

High-speed train is developing popular in China, which provides the convenient and fast transportation way, comparable to plane. The moving direction and speed of high-speed train is decided by the traction motor. Generally, a coaxial centrifugal fan is used to cool the motor and assemble in the motor casing. To ensure the reliability of the traction motor, more and more attention is paid to improve the performance of cooling fans in a wide range of rotating speed. As the train is designed to move in both directions, the traction motor is designed to rotate in both directions, so does the coaxial motor cooling fan. Symmetrical and straight blade structure is adopted to get the same performance of the fan in both forward and reverse moving directions. Therefore, the aerodynamic performance of the cooling fan is relatively not good enough, which results in relatively high aerodynamic noise. In order to analyze the cooling fan aerodynamic performance and aerodynamic noise, CFD method was performed on the full 3D model with the impeller-casing clearance. The acoustic analogy method was used to analyze the noise of the centrifugal cooling fan. In addition, the aerodynamic noise of the motor with the cooling fan was tested at different rotating speed in the semi-anechoic lab. The CFD method is verified and the results are in good agreement with the experimental results. The results show that it is necessary to consider the effects of impeller-casing leakage and the vacuum inlet condition in the simulated model to get its more accurate performance. Modified CFD model of the cooling fan was proposed here. It is suggested that the modified structure of the casing can be used to improve the performance of the cooling fan and reduce the corresponding aerodynamic noise.

Application of OpenFOAM in Numerical Simulations of High-Speed Trains Aerodynamics

2021 ◽  
Author(s):  
Panpan Lu ◽  
Bo Yin ◽  
Guowei Yang ◽  
Zhanling Ji
Keyword(s):  
Turbulent Flow ◽  
Mesh Generation ◽  
High Speed ◽  
Aerodynamic Performance ◽  
Critical Conditions ◽  
High Speed Train ◽  
Operation Conditions ◽  
Mesh Method ◽  
High Speed Trains ◽  
Inverse Distance

Abstract The present study uses openFOAM package to simulate and investigate the aerodynamic performance and characteristics of high-speed trains (velocity beyond 250 km/h) under typical and critical conditions, which include flow passing a high-speed train, and two trains meeting towards each other at the same velocity in the open air. In terms of different operation conditions, separate openFOAM solvers are adopted. For flow passing a high-speed train at a constant velocity, a steady solver for incompressible, viscous and turbulent flow is employed on a fixed mesh and the results are compared with commercial software Star CCM+. For trains meeting towards each other, overset mesh method is used in which inverse distance interpolation is taken to couple background and inner overset mesh. The built-in mesh generation tool SnappyHexMesh is utilized to generate background and inner overset mesh. In all simulations, k-ω SST two equations RANS model is used to simulate the turbulent flow.

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