Effects of infrastructure on the aerodynamic performance of a high-speed train

2020 ◽  
pp. 095440972095221
Author(s):  
Ming Wang ◽  
Xiao-Zhen Li ◽  
Jun Xiao ◽  
Hai-Qing Sha ◽  
Qi-Yang Zou
Keyword(s):  
High Speed ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
High Speed Train ◽  
Aerodynamic Coefficients ◽  
Pressure Distributions ◽  
Train Speed ◽  
Truss Bridge ◽  
Flat Ground

The aerodynamic characteristics of typical high-speed train can be affected by the operating infrastructure, which will affect the flow structure around train body. Five different infrastructure scenarios, including no infrastructure, flat ground, embankment, viaduct and truss bridge, are systemically studied. The purpose is to examine the uncertainties of aerodynamic coefficients caused by the infrastructure. Attention is drawn to variations of aerodynamic coefficients at certain yaw angles caused by the changes in crosswind and train speed. The middle car is chosen for quantifying the effects of five infrastructures by using wind tunnel test and numerical simulations, then followed by a detailed study on aerodynamic characteristics of three cars of train running on viaduct. Pressure distributions are also drawn for a better interpretation. Result shows that the uncertainties in aerodynamic coefficients becomes more obvious as the infrastructure gets complex and yaw angles get bigger. The aerodynamic coefficients of three cars with the viaduct scenario show the similar uncertainties, which are mostly affected by the change in crosswind rather than the train speed.

Experimental Studies on Aerodynamic Characteristics of Pantograph System According to the Pantograph Cover Configurations for High Speed Train

2011 ◽  
Author(s):  
Yeongbin Lee ◽  
Minho Kwak ◽  
Kyu Hong Kim ◽  
Dong-Ho Lee
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Force ◽  
Experimental Studies ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Experimental Models ◽  
High Speed Train ◽  
Drag And Lift

In this study, the aerodynamic characteristics of pantograph system according to the pantograph cover configurations for high speed train were investigated by wind tunnel test. Wind tunnel tests were conducted in the velocity range of 20∼70m/s with scaled experimental pantograph models. The experimental models were 1/4 scaled simplified pantograph system which consists of a double upper arm and a single lower arm with a square cylinder shaped panhead. The experimental model of the pantograph cover is also 1/4 scaled and were made as 4 different configurations. It is laid on the ground plate which modeled on the real roof shape of the Korean high speed train. Using a load cell, the aerodynamic force such as a lift and a drag which were acting on pantograph system were measured and the aerodynamic effects according to the various configurations of pantograph covers were investigated. In addition, the total pressure distributions of the wake regions behind the panhead of the pantograph system were measured to investigate the variations of flow pattern. From the experimental test results, we checked that the flow patterns and the aerodynamic characteristics around the pantograph systems are varied as the pantograph cover configurations. In addition, it is also found that pantograph cover induced to decrease the aerodynamic drag and lift forces. Finally, we proposed the aerodynamic improvement of pantograph cover and pantograph system for high speed train.

The Analysis of Aerodynamic Characteristics of the High-Speed Train in Different Railway Conditions under Crosswinds

2013 ◽  
Vol 774-776 ◽  
pp. 58-63
Author(s):  
Kun Ye ◽  
Ren Xian Li
Keyword(s):  
Numerical Calculation ◽  
Wind Speed ◽  
Traffic Safety ◽  
Linear Relation ◽  
High Speed ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Transverse Loads ◽  
Train Speed ◽  
Calculation Models

The numerical calculation models of the high-speed train in the straight and different radius curve railway are established. Author calculated transverse forces (moments) acting on the three sections (first train, middle train and rear train). At the same time, under with the shelter wind wall and without the wall, the change trends of side forces coefficients and rolling moments coefficients of trains with the train speed and the transverse wind speed are analyzed. Results show that, in the straight railway and curve railway, transverse loads coefficients increase with the increase of the transverse wind speed and decrease with the increase of the train speed. The transverse forces (moments) of the three sections of the train with the shelter wind wall are opposite to that without the wall. Traffic safety under crosswinds focuses on the rear train with the shelter wind wall and focuses on the first train without the wall. At the same train speed and transverse wind speed, side forces and rolling moments of trains in curve railway is greater than that of trains in straight railway. Absolute values of transverse loads coefficients decreased gradually with the increase of the radius of the curve, and their relationship basically is the linear relation.

scholarly journals Aerodynamic Performance of a High-Speed Train Passing through Three Standard Tunnel Junctions under Crosswinds

2020 ◽  
Vol 10 (11) ◽  
pp. 3664 ◽  
Author(s):  
Xiujuan Miao ◽  
Kan He ◽  
Guglielmo Minelli ◽  
Jie Zhang ◽  
Guangjun Gao ◽  
...  
Keyword(s):  
High Speed ◽  
Tunnel Junctions ◽  
Pressure Coefficient ◽  
Aerodynamic Performance ◽  
High Speed Train ◽  
Flow Conditions ◽  
Tunnel Wall ◽  
Drag And Lift ◽  
Flat Ground ◽  
Good Agreement

The aerodynamic performance of a high-speed train passing through tunnel junctions under severe crosswind condition was numerically investigated using improved delayed detached-eddy simulations (IDDES). Three ground scenarios connected with entrances and exits of tunnels were considered. In particular a flat ground, an embankment, and a bridge configuration were used. The numerical method was first validated against experimental data, showing good agreement. The results show that the ground scenario has a large effect on the train’s aerodynamic performance. The bridge case resulted in generally smaller drag and lift, as well as a lower pressure coefficient on both the train body and the inner tunnel wall, as compared to the tunnel junctions with flat ground and embankment. Furthermore, the bridge configuration contributed to the smallest pressure variation in time in the tunnel. Overall, the study gives important insights on complicated tunnel junction scenarios coupled with severe flow conditions, that, to the knowledge of the authors, were not studied before. Beside this, the results can be used for further improvements in the design of tunnels where such crosswind conditions may occur.

The Aerodynamic Characteristics of the Pantograph When the Train Passes Through the Tunnel

2017 ◽  
Author(s):  
Dilong Guo ◽  
Wen Liu ◽  
Junhao Song ◽  
Ye Zhang ◽  
Guowei Yang
Keyword(s):  
High Speed ◽  
Aerodynamic Force ◽  
Maximum Amplitude ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Expansion Waves ◽  
Compression And Expansion ◽  
High Speed Trains ◽  
Current Characteristics ◽  
Pass Through

The aerodynamic force acting on the pantograph by the airflow is obviously unsteady and has a certain vibration frequency and amplitude, while the high-speed train passes through the tunnel. In addition to the unsteady behavior in the open-air operation, the compressive and expansion waves in the tunnel will be generated due to the influence of the blocking ratio. The propagation of the compression and expansion waves in the tunnel will affect the pantograph pressure distribution and cause the pantograph stress state to change significantly, which affects the current characteristics of the pantograph. In this paper, the aerodynamic force of the pantograph is studied with the method of the IDDES combined with overset grid technique when high speed train passes through the tunnel. The results show that the aerodynamic force of the pantograph is subjected to violent oscillations when the pantograph passes through the tunnel, especially at the entrance of the tunnel, the exit of the tunnel and the expansion wave passing through the pantograph. The changes of the pantograph aerodynamic force can reach a maximum amplitude of 106%. When high-speed trains pass through tunnels at different speeds, the aerodynamic coefficients of the pantographs are roughly the same.

Aerodynamic Characteristics Analysis of High-Speed Train on Cutting under Crosswinds

2013 ◽  
Vol 300-301 ◽  
pp. 62-67
Author(s):  
Kun Ye ◽  
Ren Xian Li
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Aerodynamic Forces ◽  
Cutting Depth ◽  
Cutting Slope ◽  
Characteristics Analysis ◽  
Relationship Of ◽  
The Relationship

Cutting is an effective device to reduce crosswind loads acting on trains. The cutting depth, width and gradient of slope are important factors for design and construction of cutting. Based on numerical analysis methods of three-dimensional viscous incompressible aerodynamics equations, aerodynamic side forces and yawing moments acting on the high-speed train, with different depths and widths of cutting，are calculated and analyzed under crosswinds，meanwhile the relationship of the gradient of cutting slope and transverse aerodynamic forces acting on trains are also studied. Simulation results show that aerodynamic side forces and yawing moments acting on the train（the first, middle and rear train）decrease with the increase of cutting depth. The relationship between transverse forces (moments) coefficients acting on the three sections and the cutting depth basically is the three cubed relation. The bigger is cutting width，the worse is running stability of train. The relationship between yawing moments coefficients acting each body of the train and the cutting width approximately is the three cubed relation. The transverse Aerodynamic forces decreased gradually with the increase of the gradient of cutting slope, the relationship between yawing moments coefficients acting each body of the train and the gradient of cutting slope basically is the four cubed relation.

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