Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China. Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodyn...Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China. Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodynamic assessment, this paper primarily reviews five meaningful progresses on the aerodynamics of the train-bridge system done by Wind Tunnel Laboratory of Central South University in the past several years. Firstly, the flow around the train and the uncertainty origin of the aerodynamic assessment are described from the fluid mechanism point of view. After a brief introduction of the current aerodynamic assessment methods with their strengths and weaknesses, a new-developed TRAIN-INFRASTRUCTURE rig with the maximum launch speed of 35 m/s is introduced. Then, several benchmark studies are presented, including the statistic results of the characterized geometry parameters of the currently utilized bridge-decks, the aerodynamics of the train, and the aerodynamics of the flat box/truss bridge-decks. Upon compared with the foregoing mentioned benchmarks, this paper highlights the aerodynamic interference of the train-bridge system associated with its physical natures. Finally, a porosity-and orientation-adjustable novel wind barrier with its effects on the aerodynamics of the train-bridge system is discussed.展开更多
The effects of the different landforms of the cutting leeward on the aerodynamic performance of high-speed trains were analyzed based on the three-dimensional, steady, and incompressible Navier-Stokes equation and k-e...The effects of the different landforms of the cutting leeward on the aerodynamic performance of high-speed trains were analyzed based on the three-dimensional, steady, and incompressible Navier-Stokes equation and k-e double-equation turbulent model. Results show that aerodynamic forces increase with the cutting leeward slope decreasing. The maximum adding value of lateral force, lift force, and overturning moment are 147%, 44.3%, and 107%, respectively, when the slope varies from 0.67 to -0.67, and the changes in the cutting leeward landform have more effects on the aerodynamic performance when the train is running in the line No. 2 than in the line No. 1. The aerodynamic forces, except the resistance force, sharply increase with the slope depth decreasing. By comparing the circumstance of the cutting depth H=-8 m with that of H=8 m, the resistance force, lateral force, lift force, and overturning moment increase by 26.0%, 251%, 67.3% and 177%, respectively. With the wind angle increasing, the resistance force is nonmonotonic, whereas other forces continuously rise. Under three special landforms, the changes in the law of aerodynamic forces with the wind angle are almost similar to one another.展开更多
In this study, experiments were carried out to investigate aerodynamic characteristics of a high-speed train on viaducts in turbulent crosswinds using a 1:25 scaled sectional model wind-tunnel testing. Pressure measur...In this study, experiments were carried out to investigate aerodynamic characteristics of a high-speed train on viaducts in turbulent crosswinds using a 1:25 scaled sectional model wind-tunnel testing. Pressure measurements of two typical sections, one train-head section and one train-body section, at the windward and leeward tracks were conducted under the smooth and turbulence flows with wind attack angles between-6° and 6°, and the corresponding aerodynamic force coefficients were also calculated using the integral method. The experimental results indicate that the track position affects the mean aerodynamic characteristics of the vehicle, especially for the train-body section. The fluctuating pressure coefficients at the leeward track are more significantly affected by the bridge interference compared to those at the windward track. The effect of turbulence on the train-head section is less than that on the train-body section. Additionally, the mean aerodynamic force coefficients are almost negatively correlated to wind attack angles, which is more prominent for vehicles at the leeward track. Moreover, the lateral force plays a critical role in determining the corresponding overturning moment, especially on the train-body section.展开更多
基金Project(2017YFB1201204)supported by National Key R&D Program of ChinaProjects(51925808,U1934209)supported by the National Natural Science Foundation of China。
文摘Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China. Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodynamic assessment, this paper primarily reviews five meaningful progresses on the aerodynamics of the train-bridge system done by Wind Tunnel Laboratory of Central South University in the past several years. Firstly, the flow around the train and the uncertainty origin of the aerodynamic assessment are described from the fluid mechanism point of view. After a brief introduction of the current aerodynamic assessment methods with their strengths and weaknesses, a new-developed TRAIN-INFRASTRUCTURE rig with the maximum launch speed of 35 m/s is introduced. Then, several benchmark studies are presented, including the statistic results of the characterized geometry parameters of the currently utilized bridge-decks, the aerodynamics of the train, and the aerodynamics of the flat box/truss bridge-decks. Upon compared with the foregoing mentioned benchmarks, this paper highlights the aerodynamic interference of the train-bridge system associated with its physical natures. Finally, a porosity-and orientation-adjustable novel wind barrier with its effects on the aerodynamics of the train-bridge system is discussed.
基金Project(U1134203) supported by the National Natural Science Foundation of ChinaProject(132014) supported by Fok Ying Tong Education Foundation,ChinaProject(2011G006) supported by the Technological Research and Development Program of the Ministry of Railways,China
文摘The effects of the different landforms of the cutting leeward on the aerodynamic performance of high-speed trains were analyzed based on the three-dimensional, steady, and incompressible Navier-Stokes equation and k-e double-equation turbulent model. Results show that aerodynamic forces increase with the cutting leeward slope decreasing. The maximum adding value of lateral force, lift force, and overturning moment are 147%, 44.3%, and 107%, respectively, when the slope varies from 0.67 to -0.67, and the changes in the cutting leeward landform have more effects on the aerodynamic performance when the train is running in the line No. 2 than in the line No. 1. The aerodynamic forces, except the resistance force, sharply increase with the slope depth decreasing. By comparing the circumstance of the cutting depth H=-8 m with that of H=8 m, the resistance force, lateral force, lift force, and overturning moment increase by 26.0%, 251%, 67.3% and 177%, respectively. With the wind angle increasing, the resistance force is nonmonotonic, whereas other forces continuously rise. Under three special landforms, the changes in the law of aerodynamic forces with the wind angle are almost similar to one another.
基金Projects(51808563,51925808)supported by the National Natural Science Foundation of ChinaProject(KLWRTBMC18-03)supported by the Open Research Fund of the Key Laboratory of Wind Resistance Technology of Bridges of ChinaProject(2017YFB1201204)supported by the National Key R&D Program of China。
文摘In this study, experiments were carried out to investigate aerodynamic characteristics of a high-speed train on viaducts in turbulent crosswinds using a 1:25 scaled sectional model wind-tunnel testing. Pressure measurements of two typical sections, one train-head section and one train-body section, at the windward and leeward tracks were conducted under the smooth and turbulence flows with wind attack angles between-6° and 6°, and the corresponding aerodynamic force coefficients were also calculated using the integral method. The experimental results indicate that the track position affects the mean aerodynamic characteristics of the vehicle, especially for the train-body section. The fluctuating pressure coefficients at the leeward track are more significantly affected by the bridge interference compared to those at the windward track. The effect of turbulence on the train-head section is less than that on the train-body section. Additionally, the mean aerodynamic force coefficients are almost negatively correlated to wind attack angles, which is more prominent for vehicles at the leeward track. Moreover, the lateral force plays a critical role in determining the corresponding overturning moment, especially on the train-body section.
