Atmospheric turbulence with respect to moving ground vehicles

Cooper, Richard K.

doi:10.1016/0167-6105(84)90057-6

Cited by 117 publications

(55 citation statements)

References 4 publications

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“…how the turbulence intensity and the other indicators are experienced by a moving observer, [Coo84,WSH95]. In general a vehicle driving in a crosswind is exposed to a lower turbulence intensity because the incident flow is composed of the relative flow due to the vehicle motion, which is perfectly smooth, and to a minor extent by the turbulent natural wind.…”

Section: Wind Steady Windmentioning

confidence: 99%

Reliability based analysis of the crosswind stability of railway vehicles

Carrarini

2007

Journal of Wind Engineering and Industrial Aerodynamics

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Section: Wind Steady Windmentioning

confidence: 99%

Reliability based analysis of the crosswind stability of railway vehicles

Carrarini

2007

Journal of Wind Engineering and Industrial Aerodynamics

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“…A train will overturn when the contribution of the aerodynamic rolling moment about the leeward rail generated by a crosswind is large enough to overcome the restoring moment associated with the train weight (Gawthorpe, 1994;RSSB, 2009). Other effects include loss of ride quality through enhanced suspension vibrations (Cooper, 1984) and pantograph displacement due to wind induced lateral deflection of a train (Andersson et al, 2004;Baker and Sterling, 2009). …”

Section: Crosswindsmentioning

confidence: 99%

The Aerodynamics of a Container Freight Train

Soper

2016

Springer Theses

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This research aims to characterise the aerodynamic flow around a container freight train and investigate how changing the container loading configuration affects the magnitude of aerodynamic forces measured on a container. Experiments were carried out using a 1/25th scale moving model freight train at the University of Birmingham's TRAIN rig facility. The model was designed to enable different container loading configurations and train lengths to be tested. A series of experiments to measure slipstream velocities and static pressure were undertaken to assess the influence of container loading configuration. Experiments to measure aerodynamic loads on a container were carried out using an on-board pressure monitoring system built into a specifically designed measuring container. A collation of full scale freight data from previous studies provided a tool to validate model scale data.Analysis of freight data found it was possible to present slipstream results as a series of flow regions. Clear differences in slipstream development and aerodynamic load coefficients were observed for differing container loading configurations. Velocity and pressure magnitudes measured in the nose region were larger than values observed previously. For container loading efficiencies higher than 50% boundary layer growth stabilises rapidly, however, for less than 50% continual boundary layer growth was observed until after 100m when stabilisation occurs. Velocities in the lateral and vertical directions have magnitudes larger than previously observed; increasing the overall magnitude by ∼10%. Comparison of model and full scale data showed good agreement, indicating Reynolds number independence. An analysis of TSI safety limits found results lie close to, but do not break, existing limits. Aerodynamic load coefficients were compared with previous studies and shown to be characteristic of typical values measured for a 30• yaw angle; however, differences between static wind tunnel and moving model results were discovered.

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“…The fluctuating component is simulated as a series of superimposed sine waves. The required amplitudes, frequencies, and phases of these sine waves are calculated from the wind spectrum 'seen' by a moving vehicle outlined in reference [22]. This method ensures that the calculated wind time series has the correct spectral and correlation characteristics and is representative of real conditions.…”

Section: Calculation Of Wind Loadingsmentioning

confidence: 99%

“…• value was taken as 1.15, while for the lift force coefficient, the value was taken as 0.8, which gives the best fit to the data over the yaw angle range of most interest (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) • ). These tests were also used to obtain values of the aerodynamic weighting function.…”

Section: Class 365mentioning

confidence: 99%

Integration of Crosswind Forces into Train Dynamic Modelling

Baker

Hemida

Iwnicki

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part F:

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Abstract:In this paper a new method is used to calculate unsteady wind loadings acting on a railway vehicle. The method takes input data from wind tunnel testing or from computational fluid dynamics simulations (one example of each is presented in this article), for aerodynamic force and moment coefficients and combines these with fluctuating wind velocity time histories and train speed to produce wind force time histories on the train. This method is fast and efficient and this has allowed the wind forces to be applied to a vehicle dynamics simulation for a long length of track.Two typical vehicles (one passenger, one freight) have been modelled using the vehicle dynamics simulation package 'VAMPIRE ® ', which allows detailed modelling of the vehicle suspension and wheel-rail contact. The aerodynamic coefficients of the passenger train have been obtained from wind tunnel tests while those of the freight train have been obtained through fluid dynamic computations using large-eddy simulation. Wind loadings were calculated for the same vehicles for a range of average wind speeds and applied to the vehicle models using a user routine within theVAMPIRE package. Track irregularities measured by a track recording coach for a 40 km section of the main line route from London to King's Lynn were used as input to the vehicle simulations.The simulated vehicle behaviour was assessed against two key indicators for derailment; the Y /Q ratio, which is an indicator of wheel climb derailment, and the Q/Q value, which indicates wheel unloading and therefore potential roll over. The results show that vehicle derailment by either indicator is not predicted for either vehicle for any mean wind speed up to 20 m/s (with consequent gusts up to around 30 m/s). At a higher mean wind speed of 25 m/s derailment is predicted for the passenger vehicle and the unladen freight vehicle (but not for the laden freight vehicle).

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Atmospheric turbulence with respect to moving ground vehicles

Cited by 117 publications

References 4 publications

Reliability based analysis of the crosswind stability of railway vehicles

Reliability based analysis of the crosswind stability of railway vehicles

The Aerodynamics of a Container Freight Train

Integration of Crosswind Forces into Train Dynamic Modelling

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