The effect of the ground condition on high-speed train slipstream

Wang, Shibo; Burton, David; Herbst, Astrid H.; Sheridan, John; Thompson, Mark C.

doi:10.1016/j.jweia.2017.11.009

Cited by 79 publications

(23 citation statements)

References 19 publications

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“…The results show that the slipstream velocity obtained with the IDDES method has good consistency with experimental data. Wang et al [22] used the IDDES method to study the influence of ground conditions on the slipstream velocity of a HST. Xia et al [23] studied the effects of ground configurations on the aerodynamic performance of the HST using the IDDES method.…”

Section: Methodsmentioning

confidence: 99%

“…To accurately simulate the surface of the car body and control the number of grids at the same time, the surface grid size of the bogie and the inter-carriage gaps is 0.0065 H, the surface grid size of the other parts of the car body surface is 0.013H, and there are three local refinements around the train. The Courant−Friedrichs−Lewy number (CFL = U ∞ ∆t/ ∆x, where ∆x is the length of cells and ∆t the time step) exceeds 1 for no more than 1% of the total number of grids, and the CFL number stays below 1 for the most of grids [22,23]. A prism-layer grid generator was used to create a 20 prism-layers near the train surface with a growth rate of 1.15, with the first-layer grid having a thickness of 0.013 mm.…”

Section: Grid Strategymentioning

confidence: 99%

“…A slipstream is generated because a HST will drive the surrounding air to produce a complicated flow due to the boundary-layer effect. At present, HSTs can run at speeds of more than 300 km/h, and the resulting slipstream will threaten the safety of passengers on the platform and track-side workers, and cause damage to the trackside infrastructure [17,22]. Therefore, a large number of scholars have studied the slipstream [15,17,19,[21][22][23]31].…”

Section: Time-averaged Slipstream Velocitymentioning

confidence: 99%

“…At present, HSTs can run at speeds of more than 300 km/h, and the resulting slipstream will threaten the safety of passengers on the platform and track-side workers, and cause damage to the trackside infrastructure [17,22]. Therefore, a large number of scholars have studied the slipstream [15,17,19,[21][22][23]31]. According to the Technical Specifications for Interoperability (TSI) (European Union Agency for Railways 2014) [32] and EN CEN European Standard 2009) [33], the horizontal velocity is harmful to persons and infrastructure along the line, so in this study, we mainly consider the horizontal velocity.…”

Section: Time-averaged Slipstream Velocitymentioning

confidence: 99%

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Impact of Different Nose Lengths on Flow-Field Structure around a High-Speed Train

Guang

Zhou

et al. 2019

Applied Sciences

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In this study, the time-averaged and instantaneous slipstream velocity, time-averaged pressure, wake flows, and aerodynamic force of a high-speed train (HST) with different nose lengths are compared and analyzed using an improved delayed detached-eddy simulation (IDDES) method. Four train models were selected, with nose lengths of 4, 7, 9, and 12 m. To verify the accuracy of the numerical simulation results, they were compared with wind tunnel test results. The comparison results show that the selection of the numerical simulation method is reasonable. The research results show that with increasing nose length, the peak values of the time-averaged slipstream velocity of the trackside position (3 m from the center of track and 0.2 m from the top of rail) and the platform position (3 m from the center of track and 0.2 m from the top of rail) decrease continuously, and show a trend of rapid reduction at first, and then a slow decrease. As the nose length increased from 4 to 12 m, the time-averaged slipstream velocity at the trackside position and platform position are decreased by 57% and 19.5%, respectively. At a height of 1.6 m from the top of the rail, ΔCP max (maximum pressure coefficient), |ΔCP min| (the absolute value of minimum pressure coefficient), and ΔCP (pressure change coefficient) decrease with increasing nose length, which is similar to the peak value of time-averaged slipstream velocity, decreasing rapidly at first and then slowly. As the nose length increased from 4 to 12 m, decreases of ΔCP max, |ΔCP min|, and ΔCP by 26.5%, 58.5%, and 44.8% were shown, respectively. Different nose lengths also have a significant impact on wake flow.

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Section: Methodsmentioning

confidence: 99%

Section: Grid Strategymentioning

confidence: 99%

Section: Time-averaged Slipstream Velocitymentioning

confidence: 99%

Section: Time-averaged Slipstream Velocitymentioning

confidence: 99%

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Impact of Different Nose Lengths on Flow-Field Structure around a High-Speed Train

Guang

Zhou

et al. 2019

Applied Sciences

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“…In the present paper, the train model with three carriages will be considered, to greatly reduce the computational cost. Compared to other components, the bogies own more complicated shape and affect greatly on the flow around the train, especially the flow underneath the train body (Gao et al, 2019;Wang et al, 2018aWang et al, , 2018b. As a result, the influence of bogies on the slipstream is mainly discussed in this section, to determine a better way for the simplification of bogies.…”

Section: Simplification Of the Train Modelmentioning

confidence: 99%

Research on aerodynamic optimization of high-speed train’s slipstream

Sun

Yao

Yang

2020

Engineering Applications of Computational Fluid Mechanics

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Slipstream severely affects the safety of trackside workers and equipment. With use of profile superimposition method and vehicle modeling method, parametrization of the whole train is carried out. Then, a slipstream optimization study has been performed, taking components of slipstream in different directions at the standard heights, the drag coefficient of the whole train and the volume of the driving cab as the design objectives. For each design objective, one unique ε-TSVR surrogate model has been constructed. Six final Pareto sets have been obtained on the base of six groups of different fitness functions by using multi-objective particle swarm method. Results reveal that the volume of the driving cab keeps almost the same, compared to the original shape. The velocity components of train-induced wind at the positions 0.2 and 1.4 m above the top of the rail, and the drag coefficient of the train are reduced by 11.6%, 33.9%, 24.7%, 25.9% and 13.0% respectively. Sensitivity analysis reveals that the length of the streamline, the height of the train and the width of the train influence significantly on the aerodynamic performance, and the train with a tall and thin streamline will benefit in reducing the slipstream and aerodynamic drag.

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