View Single Post
Old 01-11-2021, 03:23 PM   #1 (permalink)
JulianEdgar
Banned
 
Join Date: Nov 2017
Location: Australia
Posts: 2,060
Thanks: 107
Thanked 1,605 Times in 1,136 Posts
Fascinating free paper - but it's on trains, not cars

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:


  Reply With Quote
The Following 3 Users Say Thank You to JulianEdgar For This Useful Post:
aerohead (01-13-2021), BamZipPow (02-03-2021), freebeard (01-11-2021)