Study of aerodynamic coefficients used to estimate critical wind speed for vehicle overturning

Kikuchi, Katsuhiro; Suzuki, Minoru

doi:10.1016/j.jweia.2015.09.003

Cited by 38 publications

(14 citation statements)

References 15 publications

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“…In 1972, Kunieda [4] from the Japanese National Railways recommended a technique for the static analysis of a railway vehicle overturning due to a crosswind, which is called 'Kunieda's Formula'. In the feedback review, the critical wind speed for vehicle overturning as calculated using Kunieda's formula showed good agreement with those estimated for actual overturning accidents at that time [11]. Since then, Kunieda's formula has been extensively adopted to assess the safety of newly designed vehicles (to avoid overturning accidents) in Japan.…”

Section: Introductionmentioning

confidence: 73%

“…In 2015, Kikuchi and Suzuki [11] has systematically investigated the influence of aerodynamic force coefficients on the critical wind speed for vehicle overturning for metergauged line vehicles. It is done by calculating the critical wind speed for vehicle overturning for a given amount of change in the aerodynamic force coefficients.…”

Section: Introductionmentioning

confidence: 99%

“…This methodology is chosen due to the fact that it is an improvement from the previous technique developed by Kunieda[4] and a simplification of static analyses over the more complicated method in dynamic analyses by most of European countries. Based on the study by Kikuchi and Suzuki [11],critical wind speed for vehicle overturning varies with respect to the different incident flow angle (Ψ). Since the result for the critical wind speed is highly depended on the external forces that act on the vehicle, the value will be critical at high incident flow angle values in which most of the aerodynamic loads were at its optimum values.…”

Section: Introductionmentioning

confidence: 99%

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Safety Guideline for a Generic Train Travelling on Different Platform Scenarios under the Influence of Crosswind

Ishak¹

2020

IJATCSE

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The rapid development of train industry has allowed for the train to travel at much higher speeds. However, at high speed, issues regarding the resulting aerodynamic loads are a major concern especially when trains travelling under the influence of crosswind conditions. In this study, numerical techniques were adopted to assess the aerodynamic effects on the generic train as it is moving on different platform conditions (i.e. flat ground, embankment and bridge). The embankment case is varied based on the slope angle while the bridge case is differed based on the shape of girder wing. The influence of crosswind on the moving train is also conducted in which the incident flow angle (Ψ) is varied from 0º to 90º. Results shows that the aerodynamic loads are magnified as the train travels on higher altitude platforms. Analysis of the results can also be categorised into two flow regimes based on the incident flow angle (Ψ). The maximum value for lift were found at small range of incident flow angle (Ψ ≤ 45º) or also known as the slender body-flow regime. Otherwise, at larger incident flow angle (Ψ ≥ 60º) or also known as the bluff body-flow regime, the side force and the rolling moment reached its critical values. Lastly, the results from the aerodynamic loads attained in this study is utilized for the assessment on the safety guidelines for train operation based on the 'critical wind speed for vehicle overturning'. The study concludes that the 'critical wind speed for vehicle overturning' (U R,critical ) is the worst condition for a train moving on an embankment under the influence of crosswind which also led to the slowest 'train critical speed' (U t,critical ). At a certain crosswind condition (Ψ), for any kind of rail vehicles travelling on any kind of infrastructures, the result of U R,critical was found to be on the same linear line relationship with respect to U t,critical .

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Safety Guideline for a Generic Train Travelling on Different Platform Scenarios under the Influence of Crosswind

Ishak¹

2020

IJATCSE

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“…Mao et al [15] carried out the studies of the influence of crosswind characteristics on aerodynamic forces acted on high-speed train by theoretical analysis, model experiment, air fluid simulation and multi-body system dynamics simulation. Kikuchi et al [16] obtained the aerodynamic force coefficients from wind tunnel experiment and a full-scale model field test firstly, and then compared with the respective experiments, they also evaluated the effects of aerodynamic force coefficients by using the critical wind speed determined from the aerodynamic force coefficients. Zhuang and Lu [17] studied the yaw effect of the side flow around a high-speed train by means of large eddy simulation, and concluded that the time-dependent aerodynamic forces are dominated by several energetic frequencies and the frequency range is broadened to a higher extent for the large yaw angle through spectral analysis.…”

Section: Introductionmentioning

confidence: 99%

Hunting stability analysis for high-speed trains under crosswinds

Mao

Zeng

2020

SN Appl. Sci.

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A 17-DOF mathematical model for a high-speed vehicle under steady crosswinds is established, and the nonlinear wheel/ rail contact geometry and interactive forces are considered. Most importantly, the wheel profiles due to wears with the increase of operating mileage are measured, which have been used to calculate the wheel/rail contact geometry and equivalent conicity. The motion differential equation of the vehicle system is set up, and a program is written to calculate the critical speed under the corresponding parameters considering the vehicle running on straight and curved tracks with crosswind blowing to outer/inner rail. The linearization of the nonlinear vehicle system is conducted, and the critical speed is determined according to the eigenvalues of the linearized system in the equilibrium position. The results demonstrate that the critical speed of the vehicle system is significantly influenced by crosswind. The critical speed increases as the crosswind velocity is increasing when the crosswind blows to inner rail on curves, while it decreases as the crosswind blows to outer rail. And the wears of the wheel profiles also greatly contribute to the hunting stability of the vehicle system due to the resulted high equivalent conicity of wheel/rail contact. The critical speed increases with the increase of curve radius and super-elevation. It is also known through calculations that the derailment safety of the vehicle on curved track is greatly affected by crosswinds.

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“…The wind speed in the atmospheric boundary layer normally grows as height increases, leaving aside the fact that at ground level there may be other elements which could eventually slow down the wind speed, such as vegetation. This increase in the risk of overturning has caught the attention of several studies, which have been focused on the characterisation of the aerodynamic response to cross-winds of either road vehicles [14][15][16][17][18][19] or rolling stock [20][21][22][23][24][25][26] travelling on bridges.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of cross-flow above a railway bridge equipped with solid windbreaks

Avila-Sanchez

López-García

Cuerva

et al. 2016

Engineering Structures

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The flow field above a two dimensional model of a railway bridge equipped with solid windbreaks is analysed in a wind tunnel. Particle image velocimetry (PIV) is used to measure the flow velocity in planes perpendicular to the bridge span. The mean velocity components, the two-component turbulent kinetic energy, the turbulence intensities of the velocity fluctuation components and the Reynolds shear stress above the bridge deck are presented. The flow patterns based on the streamlines of the average flow field are analysed. The inclusion of a windbreak produces a separation bubble, that is locked to the bridge deck due to presence of the leeward fence. Special attention is paid to the analysis of the flow field characteristics along the vertical profiles above the railway tracks. The inclusion of the windbreak leads both to an increase of the mean velocity and the turbulence intensity around the catenary contact wires. On the other hand, the flow in the region close to the bridge deck is slowed-down. The effect of the size of the final interrogation window used in the PIV analysis is considered, more particularly on the determination of the mean velocity and turbulence intensity. The results show that a decrease of the final interrogation window leads to an increase of the turbulence intensity when there are no wind protection devices installed on the bridge.

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Study of aerodynamic coefficients used to estimate critical wind speed for vehicle overturning

Cited by 38 publications

References 15 publications

Safety Guideline for a Generic Train Travelling on Different Platform Scenarios under the Influence of Crosswind

Safety Guideline for a Generic Train Travelling on Different Platform Scenarios under the Influence of Crosswind

Hunting stability analysis for high-speed trains under crosswinds

Characterisation of cross-flow above a railway bridge equipped with solid windbreaks

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