https://www.sciencedirect.com/scienc...dgcid=coauthor
What a great paper! Well written and fascinating results. Worth reading for anyone interested in vehicle aero - not just trains.
They instrumented a shipping container on a train, placing pressure taps/front and back.
Key points to look at:
- how Cd is calculated from just front and rear pressures
- how Cd varied little with speed (as expected) but varied a lot with crosswinds - see graph below
- the different pressure patterns on the container with crosswinds
- how Reynold's numbers are important, because the 'length' criterion varies with the position of the container along the train
- how boundary layer thickness is important - and again varies with position along the train
And, for anyone just interested in tech, how they instrumented (and then retrieved data from) a freight train travelling across one-third of Australia, with no researchers on board.
Variation in drag with wind:
