View Single Post
Old 08-31-2020, 04:44 PM   #6 (permalink)
JulianEdgar
Banned
 
Join Date: Nov 2017
Location: Australia
Posts: 2,060
Thanks: 107
Thanked 1,594 Times in 1,131 Posts
Quote:
Originally Posted by kach22i View Post
What kind of variations or errors will we see in a small wind tunnel that are not present at the large wind tunnel? Can these variations be corrected for and adjusted as with polling data?
I think every single factor that is measurable will likely be in error. 'Low Speed Wind Tunnel Testing (Barlow/Rae/Pope) is the book to look at ('low speed', as in sub-sonic). It has a large number of chapters devoted to corrections.

Here's a key passage from that book relating to wind tunnel test section size:



So yes you can see from this that correction factors exist, but the recommendation (AFAIK) still remains at a max of 5 per cent blockage.

As I said, you can be sure if smaller, cheaper wind tunnels were fine, car manufacturers, race teams, etc, wouldn't have all built huge (and massively expensive) wind tunnels.

Last edited by JulianEdgar; 08-31-2020 at 05:11 PM.. Reason: typo
  Reply With Quote
The Following User Says Thank You to JulianEdgar For This Useful Post:
aerohead (09-11-2020)