CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Lift and Drag Equations

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   January 12, 2012, 14:11
Default Lift and Drag Equations
New Member
Join Date: Jan 2012
Posts: 11
Rep Power: 7
Tom A is on a distinguished road
Hi, I am having some difficulty in understanding how to calculate forces using information obtained from fluent. The lift and drag equations I am using are:

D = 1/2*density*velocity^2*A*Cd
L = 1/2*density*velocity^2*a*Cl

However there seems to be different conventions for what to use as the reference area, A. For example on the wikipedia article it lists several different reference areas like airplane it says the planform area is typically used but for submerged bodies the wetted surface area is typically used. It seems like Cd and Cl values can vary depending on the application so how does Fluent calculate Cd and Cl and how should I use them?

Tom A is offline   Reply With Quote

Old   January 14, 2012, 00:46
Senior Member
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 1,931
Rep Power: 26
LuckyTran will become famous soon enoughLuckyTran will become famous soon enough
To my knowledge, Fluent does not calculate the drag coefficient and lift coefficients (most likely because there are too many conventions).

Fluent however can report the drag and lift forces which can then be used to calculate the drag and lift coefficients according to your definition of those terms.

You should use the drag and lift coefficients for your particular application to avoid confusion with others in your field, follow the convention rather than establish your own (unless you have a better one). Otherwise, use the definitions that you are most comfortable with. It is entirely up to you.

Check out the fluent help file or manual for detailed information. It is much more like a textbook.
LuckyTran is offline   Reply With Quote


Thread Tools
Display Modes

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 On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
How does FLUENT calculate lift and drag? xTamx420 FLUENT 0 May 30, 2011 13:35
Lift and Drag Monitor Point Values Converging to Zero Josh CFX 24 May 9, 2011 10:38
Lift and Drag ??? Yogibear STAR-CCM+ 4 June 20, 2010 10:11
Correct lift but wrong pressure drag - possible? zx Main CFD Forum 4 July 27, 2007 23:38
Fluid mechanics / drag & lift Jamcam Main CFD Forum 0 October 31, 2002 05:39

All times are GMT -4. The time now is 03:27.