Aerodynamics

Improvement in aerodynamic efficiency of a train can lead to significant reductions in the amount of fuel required, helping to meet decarbonisation targets.

These effects are not only apparent for high-speed passenger trains but also slower moving freight trains, which are traditionally highly bluff-shaped vehicles with little aerodynamic consideration. Better understanding of these key aerodynamic parameters can improve train modelling simulations, leading to better train pathing diagrams and timetables. This will undoubtedly improve train management leading to less fuel consumption and greater efficiency.

Unlike other vehicles, it is not only the aerodynamic drag that is important for trains, however. The highly turbulent aerodynamic flows created with large velocity and pressure magnitudes can create safety issues when interacting with passengers waiting on platforms or trackside workers, railway infrastructure when passed by the train (such as noise barriers and hoardings), or through interactions with local wind conditions which may result in train instabilities, which in the worst case scenario can lead to overturning. There are also issues related to pressure waves created as a train enters into a tunnel, which can cause effects ranging from aural discomfort for passengers to micro-pressure waves exiting the tunnel as sonic booms.

Related to the theme of decarbonisation is that of pollution dispersion.

Exhaust emissions from diesel rolling stock will be directly influenced by the aerodynamic flow surrounding moving vehicles, potentially leading to the intake of pollutants back into the train through the air conditioning intakes.

Research areas include:

  • Aerodynamic drag and slipstream velocity measurements
  • Static pressure pulse measurements and sonic boom
  • Pressures acting on the train
  • The effects of crosswinds at various yaw angles, train effects and local wind environment analysis
  • Aerodynamic pressures acting on trackside structures, effects of a train passing through a tunnel and effects due to train design and size
  • Design optimisation
  • Aerodynamic loads affecting ballast flight and slab track running
  • Pollutant dispersion

If you would like to get in touch, please email: railway@contacts.bham.ac.uk.