Archive for the 'Physics' Category

Train Aerodynamics (part 1)

The metro trains experience an interesting set of aerodynamic effects in the tunnels. The train itself is used to circulate air through the tunnels and ventilation systems (hence its shape is not very aerodynamic at all, not that it matters at these low speeds). Of course, the main aerodynamic effect on the train is the drag force. On long sloped down sections of track (where the train moves without any power input) the aerodynamic drag can provide about 5 km/h of speed difference as train accelerates from 30 km/h to 80 km/h.

For Subtransit, I’m working on an aerodynamic model that would account for both drag produced by the train as it moves through the tunnel as well as additional torque force produced when train passes by a ventilation shaft. Currently, the CFD results are only preliminary, although there are a few interesting results already.

Continue reading ‘Train Aerodynamics (part 1)’