Karmann Vortex Like Wake Flow behind a High Speed Train and its Control.

1993 ◽  
Vol 13 (51) ◽  
pp. 236-240
Author(s):  
Yasuaki KOHAMA
Keyword(s):  
High Speed ◽  
Wake Flow ◽  
High Speed Train

On the correlation between aerodynamic drag and wake flow for a generic high-speed train

2021 ◽  
Vol 215 ◽  
pp. 104698
Author(s):  
Xiao-Bai Li ◽  
Xi-Feng Liang ◽  
Zhe Wang ◽  
Xiao-Hui Xiong ◽  
Guang Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Aerodynamic Drag ◽  
Wake Flow ◽  
High Speed Train

Effect of the ballast height on the slipstream and wake flow of high-speed train

2020 ◽  
Vol 207 ◽  
pp. 104404
Author(s):  
Xi-feng Liang ◽  
Xin Zhang ◽  
Guang Chen ◽  
Xiao-bai Li
Keyword(s):  
High Speed ◽  
Wake Flow ◽  
High Speed Train

An IDDES investigation of Jacobs bogie effects on the slipstream and wake flow of a high-speed train

2020 ◽  
Vol 202 ◽  
pp. 104233
Author(s):  
Jiabin Wang ◽  
Guglielmo Minelli ◽  
Tianyun Dong ◽  
Kan He ◽  
Guangjun Gao ◽  
...  
Keyword(s):  
High Speed ◽  
Wake Flow ◽  
High Speed Train

scholarly journals Effects of Bogies on the Wake Flow of a High-Speed Train

2019 ◽  
Vol 9 (4) ◽  
pp. 759 ◽  
Author(s):  
Wen Liu ◽  
Dilong Guo ◽  
Zijian Zhang ◽  
Dawei Chen ◽  
Guowei Yang
Keyword(s):  
High Speed ◽  
Wake Flow ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Wake Flows ◽  
Delayed Detached Eddy Simulation ◽  
Mode Decomposition ◽  
Unsteady Characteristics

The wake region of high-speed trains is an area of complex turbulent flow characterized by the periodic generation and shedding of vortices, which causes discomfort to passengers and affects the stability and safety of the train. In this study, the unsteady characteristics of the wake flows of three 1:1 scale China Railway High-Speed 380A (CRH380A) high-speed train models with different degrees of simplification were numerically investigated using the improved delayed detached eddy simulation (IDDES) method. Analyses of the aerodynamic forces, train-induced slipstream, and turbulent kinetic energy (TKE) were conducted to determine the effects of the bogies on the wake flow of the high-speed train. It was found that the existence of bogies on the bottom of the train, especially the last bogie, not only enhanced the wake flow but also introduced large perturbances into the wake flow. Moreover, the generation and evolution of the vortices in the wake flows were determined by analyzing the instantaneous flow fields and coherent flow structures that were obtained by the dynamic mode decomposition (DMD) method. The results showed that a pair of large, counter-rotating streamwise vortices in the real model of the high-speed train was generated by the cowcatcher and their intensity was significantly enhanced by perturbances that were introduced by the bogies on the bottom of the train.

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

2019 ◽  
Vol 9 (21) ◽  
pp. 4573 ◽  
Author(s):  
Xianli Li ◽  
Guang Chen ◽  
Dan Zhou ◽  
Zhengwei Chen
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Aerodynamic Force ◽  
Pressure Coefficient ◽  
Wake Flow ◽  
Maximum Pressure ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Rapid Reduction ◽  
Comparison Results

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.

The effect of bogie fairings on the slipstream and wake flow of a high-speed train. An IDDES study

2019 ◽  
Vol 191 ◽  
pp. 183-202 ◽  
Author(s):  
Jiabin Wang ◽  
Guglielmo Minelli ◽  
Tianyun Dong ◽  
Guang Chen ◽  
Sinisa Krajnović
Keyword(s):  
High Speed ◽  
Wake Flow ◽  
High Speed Train
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