×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

GROUND EFFECTS DIFFUSERS DATA

GROUND EFFECTS DIFFUSERS DATA

GROUND EFFECTS DIFFUSERS DATA

(OP)

I’ve searched the internet for a long time for hard data on ground effects diffuser design. Finally I found what I thought was a gold mine: Ground Effects Aerodynamics of Race Cars.

SITE:http://eprints.soton.ac.uk/42969/1/GetPDFServlet.pdf

Actually it’s a review of many ground effects experiments in university wind tunnels, many with moving ground planes. Good stuff.

So I went to page 41, and there it was, the GOLD!: two charts showing lift and drag curves (in the Y axis) as a function of h/d (in the X axis). The variable h is defined (p40, fig. 12) as the vertical dimension of the diffuser entrance, AKA ride height. What about the variable “d” ? No definition or explanation is given, as far as I can tell. Do any of the pros on this site have a clue what “d” is? Thanks, Paul6

RE: GROUND EFFECTS DIFFUSERS DATA

"d" is probably a dimension - say the width of the diffuser would be my guess???

RE: GROUND EFFECTS DIFFUSERS DATA

(OP)
Mike, I think you're right. It is very likely to be a dimension. From the diagram on page 40, the only important missing dimension is the height of the diffuser exit. If this were to be the mysterious "d", h/d would be the inverse of the expansion ration, a very important factor. But why the inverse?

Paul6

RE: GROUND EFFECTS DIFFUSERS DATA

(OP)
Correction, I meant expansion ratio.

RE: GROUND EFFECTS DIFFUSERS DATA

NO idea - it was just a guess

RE: GROUND EFFECTS DIFFUSERS DATA

h/d could effectively be a typo for h/Ld Ld=length of duct, or from the next section h/theta d

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close