Wall Interference Effect on the Aerodynamics of a High-speed Train

Xia, Chao; Shan, Xizhuang; Yang, Zhigang

doi:10.1016/j.proeng.2015.11.301

Cited by 6 publications

(7 citation statements)

References 7 publications

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“…As shown in Table 3, the maximum error in the C l values obtained from the wind tunnel test and the numerical simulations performed using the current mesh was as high as 46%; this was because of the complex structure of the train bottom and the distance between the train and the ballast. 18,37,38 On the other hand, the maximum error in the C d values obtained from the wind tunnel test and the numerical simulations performed using the current mesh was less than 3%, meaning that the mesh size and simulation method used in this study were suitable for achieving accurate numerical results.…”

Section: Algorithm Validationmentioning

confidence: 79%

Numerical simulation of the effects of obstacle deflectors on the aerodynamic performance of stationary high-speed trains at two yaw angles

Niu

Zhou

Liang

2017

Proceedings of the Institution of Mechanical Engineers, Part F:

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In this study, based on the shear-stress transport-! turbulent model, the improved delayed detached eddy simulation method has been used to simulate the unsteady aerodynamic performance of trains with different obstacle deflectors at two yaw angles (0 and 15). The numerical algorithm is used and some of the numerical results are verified through wind tunnel tests. By comparing and analysing the obtained results, the effects of the obstacle deflectors on the force of the trains as well as the pressure and flow structure around the trains are elucidated. The results show that the obstacle deflectors primarily affect the flow field at the bottom of the head car as well as the wake flow, and that the internal oblique-type obstacle deflector (IOOD) markedly improves the aerodynamic performance of the trains, by decreasing most of the aerodynamic forces of the train cars and minimising their fluctuations. Further, a nonzero yaw angle weakens or even changes the effect of the IOOD on the aerodynamic forces of the train cars. However, the effect of the IOOD is more on the tail car.

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Section: Algorithm Validationmentioning

confidence: 79%

Numerical simulation of the effects of obstacle deflectors on the aerodynamic performance of stationary high-speed trains at two yaw angles

Niu

Zhou

Liang

2017

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…The basic tools for studying aerodynamic behavior of a HST are full-scale testing, 2,3 model scale testing, including wind tunnel testing [4][5][6][7][8][9][10] and moving model rig [11][12][13] and computational fluid dynamics (CFD). [14][15][16][17][18][19][20][21][22][23] As an indispensable method, wind tunnel testing has the advantage on having controlled environmental conditions, easy operation and less run to run variance. With wind tunnel testing, a series of train aerodynamic issues can be researched: drag reduction techniques, crosswind stability, aeroacoustics and slipstream.…”

Section: Introductionmentioning

confidence: 99%

“…Recently due to improved accuracy of CFD, it has become a viable tool for the HST aerodynamic development. [14][15][16][17][18][19][20][21][22][23] CFD is significantly cheaper and easier than an experimental study 26 and it can simulate the different ground conditions without limits existed in the practical wind tunnel testing, for instance, the moving ground can be simulated easily. Therefore, it offers the possibility to simulate the novel concepts.…”

Section: Introductionmentioning

confidence: 99%

“…All above studies are investigated experimentally, and most of the GSS are employed just in academic research due to the high technical effort, hence the common approach in industry is to simply mount the HST on the stationary ground. 4,7,19,22,25 Theoretically, a single moving ground, which is wider and longer than the train models, can provide an ideal underbody flow for a HST. However, several practical problems are related to using a wider single moving ground in a HST wind tunnel testing.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of different ground simulation systems on the flow around a high-speed train

Xia

Shan

Yang

2016

Proceedings of the Institution of Mechanical Engineers, Part F:

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The influence of different ground simulation systems on the air flow around a high-speed train with zero yaw angle is investigated. Force values, force development graphs, surface pressures, the underbody flow and the wake are studied in detail with Computational Fluid Dynamics, which is initially validated by wind tunnel testing. It shows that the stationary ground has severe deviations from the full moving ground on the aerodynamic performance due to the inaccurate pressure distribution on the underbody. This is mainly attributed to the high level of interaction between the underbody and the boundary layer development. In addition, a ground boundary layer separation bubble can be observed under the tail end of the train for the stationary ground on account of insufficient energy to overcome the increasing adverse pressure gradient. In order to guarantee a correct underbody flow, a partially moving ground is proposed, including the ''3-moving ground'' and the ''1-moving ground''. Such ground simulation systems are well compatible with the fixed rail tracks and the bottom support struts compared to the full moving ground. As a conceivable method to reduce the influence of the boundary layer, raising the high-speed train model with different ground clearances is also studied. Overall, the 3-moving ground is suggested to be the best choice for the ground simulation systems in high speed train wind tunnel testing.

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“…18–23 Xia et al. 24 studied the ground effect on the aerodynamic performance of trains, and found that moving ground decreases the aerodynamic forces of trains in when compared to that of the stationary ground. By increasing the distance between the train and the stationary ground, the aerodynamic forces of the train also increased.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the aerodynamic characteristics of a train subjected to different ground conditions

Niu

Liang

Zhou

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part F:

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Due to the rapid development of high-speed railways and the increasing speed of trains, the aerodynamic phenomenon caused by moving trains could be affected. Therefore, the scaled model test has been widely used to simulate the aerodynamic performance of the stationary train in wind tunnel. However, it is difficult to disregard the influence of the ground effect on the aerodynamic performance of trains. In this study, the delayed detached eddy simulation based on the shear stress transport-! turbulence model is used to investigate the aerodynamic performance of trains on three ground conditions (stationary floor þ stationary ballast, stationary ground þ stationary ballast, and stationary ballast). The numerical method used in this paper is verified by a wind tunnel test. The way the three ground conditions influence the flow field around the train is also analyzed. The results show that the ground condition affects the thickness of the ballast boundary layers without a train, thickness of the train boundary layers, train drag, distribution of pressure and velocity along the train, and the size of the wake region; however, the ground condition had a little effect on the flow structures around the train tail. These findings can help in designing the wind tunnel experiment.

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Wall Interference Effect on the Aerodynamics of a High-speed Train

Cited by 6 publications

References 7 publications

Numerical simulation of the effects of obstacle deflectors on the aerodynamic performance of stationary high-speed trains at two yaw angles

Numerical simulation of the effects of obstacle deflectors on the aerodynamic performance of stationary high-speed trains at two yaw angles

Comparison of different ground simulation systems on the flow around a high-speed train

Numerical investigation of the aerodynamic characteristics of a train subjected to different ground conditions

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