CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens

Lift and Drag Coefficients

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 12, 2007, 11:36
Default Lift and Drag Coefficients
  #1
xdm
Guest
 
Posts: n/a
Hi guys, can you tell me the way to calculate lift and drag coefficients for a wing with star cd.

Thanks
  Reply With Quote

Old   February 13, 2007, 05:27
Default Re: Lift and Drag Coefficients
  #2
Kasper Skriver
Guest
 
Posts: n/a
You will have to somehow extract the forces. Normal and tangential. Then you would be able to calculate the coefficients from projected areas.

  Reply With Quote

Old   February 13, 2007, 06:14
Default Re: Lift and Drag Coefficients
  #3
xdm
Guest
 
Posts: n/a
Kasper, i know the theory! I just want to know the commands in pro-star!
  Reply With Quote

Old   February 13, 2007, 06:18
Default Re: Lift and Drag Coefficients
  #4
Kasper Skriver
Guest
 
Posts: n/a
Ho much will you pay me then?

  Reply With Quote

Old   February 13, 2007, 06:28
Default Re: Lift and Drag Coefficients
  #5
Kasper Skriver
Guest
 
Posts: n/a
In the star_uguide.pdf at page 9-26

7. Calculating aerodynamic coefficients â€" command ACOEFF.

This facility works in conjunction with values of total force components at the wall, loaded via the Wall Post Data dialog. A set of wall shells, enveloping the object whose coefficients are to be calculated, must also be created using a CSET operation.

a) add some shells on the wall boundary

b) do some wall post data

c) command acoeff, try help acoeff

d) pay my bills

BR and hope its working

Kasper Skriver
  Reply With Quote

Old   February 13, 2007, 14:50
Default Re: Lift and Drag Coefficients
  #6
paulh
Guest
 
Posts: n/a
You might also try to use 'Monitor Boundary Behavior' and export the forces per iteration. At the end of the analysis, import the text file into your favorite spreadsheet and do the math to get Cd & Cl. I would use this to judge convergence. I don't have any experience with wings, but for pass cars and heavy vehicles, drag settles down significantly after the residuals flatten out. However, use the acoef command for the final value. Although the trends are correct, there seems to be a problem with the absolute values coming out the boundary monitoring routines.
  Reply With Quote

Old   February 14, 2007, 09:19
Default Re: Lift and Drag Coefficients
  #7
Tobbe
Guest
 
Posts: n/a
CD-Adapco have a posdat subroutine for monitoring drag and lift. If you ask nicely they will probably give it to you for free. Otherwise, if its only drag and lift you are interested in and the geometry just is a simple wing, I would recomend using Star CCM+ instead, its much easier to monitor drag and lift in CCM+.
  Reply With Quote

Old   April 8, 2007, 18:55
Default gambit modelling and fluent analysis of jeep
  #8
talha
Guest
 
Posts: n/a
i would like to know and recieve the 3D modelling and analysis of jeep using gambit and fluent.
  Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
how to set lift and drag coefficients in force mon alagesanj FLUENT 0 November 16, 2008 21:47
Calculation of lift and drag coefficients Prachi CFX 3 August 14, 2007 15:05
airfoil: drag and lift coefficients Pedro Clode FLUENT 1 January 1, 2007 13:44
Regarding lift/pressure/drag coefficients quarkz Main CFD Forum 0 December 22, 2005 00:07
pressure. lift and drag coefficients waqar mahboob Main CFD Forum 0 July 25, 1998 04:34


All times are GMT -4. The time now is 03:07.