Crosswind stability and unsteady aerodynamics in vehicle design

Researchers

• Professor Mats Berg (Project leader)
• Lic.Tech. (PhD student)
• Dr. Ben Diedrichs
• Professor Sebastian Stichel

Sources of funding

KTH, Vinnova, Scania, Volvo, Saab, Bombardier, A2Zound, VTI, Trafikverket.
This is a project within the Vinnova Centre for ECO² Vehicle Design.

Research Direction

This project comprises both vehicle aerodynamics and vehicle dynamics, and is applied to both rail and road vehicles.

A significant challenge is to carry out unsteady fluid dynamics simulations, supporting the vehicle dynamics studies including overturning risk. A case study selected for the rail application is the Green Train, making use of the field tests carried out in recent years to investigate the lateral dynamics in more detail. Wind gusts have then been introduced in the simulations to investigate various overturning scenarios.

The overall goal of the project is to suggest less wind sensitive vehicle designs, mainly through the external shaping as well as the vehicle mass and suspension properties.

Publications

• Thomas D, Berg M, Diedrichs B and Stichel S: Rail vehicle response to lateral carbody excitations imitating crosswind. Proceedings of the 22nd International Symposium on Dynamics of Vehicles on Roads and Tracks, IAVSD'11, Manchester, August 14-19 2011.
• Diedrichs B: Aerodynamic crosswind stability of a regional train model, Proc. IMechE Journal of Rail and Rapid Transit, Vol 224, pp 580-591, November 2010.
• Thomas D, Diedrichs B, Berg M and Stichel S: Dynamics of a high-speed rail vehicle negotiating curves at unsteady crosswind. Journal of Rail and Rapid Transit, Vol. 224, No. F6, pp. 567-579, November 2010.
• Thomas D, Berg M and Stichel S: Measurements and simulations of rail vehicle dynamics with respect to overturning risk. Vehicle System Dynamics, Vol. 48, No. 1, pp. 97-112, January 2010.
• Thomas D, Diedrichs B, Berg M and Stichel S: Dynamics of a high-speed rail vehicle negotiating curves at unsteady crosswind. Proceedings of the 21st International Symposium on Dynamics of Vehicles on Roads and Tracks, IAVSD'09, Stockholm, August 17-21 2009.
• Thomas D: Lateral stability of high-speed trains at unsteady crosswind. Licentiate Thesis, TRITA AVE 2009:79, ISBN 978-91-7415-473-3, Stockholm, Sweden, 2009.
• Favre T, Diedrichs B and Efraimsson G: Detached-eddy simulations applied to unsteady crosswind aerodynamics of ground vehicles. 3rd Symposium on Hyrbrid RANS-LES Methods, Gdansk, June 2009.
• Diedrichs B: Unsteady aerodynamic crosswind stability of a high-speed train subjected to gusts of various rates. Euromech Colloquium 509: Vehicle Aerodynamics – External Aerodynamics of Railway Vehicles, Trucks, Buses and Cars, Berlin, March 24-25 2009. A corresponding paper has also been accepted.
• Favre T, Efraimsson G and Diedrichs B: Numerical investigation of unsteady crosswind vehicle aerodynamics using time-dependent inflow conditions. 7th MIRA International Vehicle Aerodynamics Conference, Coventry, October 22-23, 2008.
• Thomas D, Berg M and Stichel S: Measurements and simulations of rail vehicle dynamics with respect to overturning risk. XXII International Congress of Theoretical and Applied Mechanics (ICTAM), Adelaide, August 24-29, 2008. Also in Vehicle System Dynamics, Vol. 48, No. 1, pp. 97-112, January 2010.
• Diedrichs B: Aerodynamic calculations of crosswind stability of a high-speed train using control volumes of arbitrary polyhedral shape. VI International Colloquium on Bluff Bodies Aerodynamics & Applications (BBAA), Milan, July 20-24, 2008. A corresponding paper has also been published.
• Favre T and Thomas D: Transient crosswind stability of vehicles – A literature survey. Report TRITA AVE 2007:60, Centre for ECO² Vehicle Design, KTH, 2007.