CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

liftDir and dragDir vectors in a moving zone

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 17, 2021, 01:33
Default liftDir and dragDir vectors in a moving zone
  #1
New Member
 
D.Frank
Join Date: Feb 2021
Posts: 4
Rep Power: 2
NotOverUnderated is on a distinguished road
Hi,

I am running a sliding mesh simulation (fixed region + rotating cellZone) and I would like to use forceCoeffs function object to compute the lift and drag coefficients for some airfoils that are located in the rotating cellZone.

I have a question about the vectors liftDir and dragDir: Are they specified in a fixed frame of reference or they are relative to the cellZone on which the airfoil is located? in other words, does OpenFOAM automatically take care of rotating these two vectors (liftDir and dragDir) accordingly when the cellZone (in which the airfoil is located) is rotating?

I appreciate your help.

Best regards
NotOverUnderated is offline   Reply With Quote

Old   February 17, 2021, 16:26
Default Update on the thread
  #2
New Member
 
D.Frank
Join Date: Feb 2021
Posts: 4
Rep Power: 2
NotOverUnderated is on a distinguished road
I've found that OpenFOAM v7 does this automatically* (when it computes the lift and drag it actually uses the tangential and the normal forces but this is not the case for OpenFOAM v6 or OpenFOAM v2006.

I don't know how this feature was introduced in OpenFOAM v7 without any details (I can't find anything about it) or even how to disable that to restore the old behaviour (similar to OF6, etc.).


* I've compared the output of forces & forceCoeffs function objects of both OF6 and OF7 and I've parsed the contents manually using a python script to make this conclusion.

Could someone please explain or give a link to explain when OF7 implemented this feature?

Thanks
NotOverUnderated is offline   Reply With Quote

Reply

Tags
drag, forcecoeffs, forces, functionobjects, openfoam

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
OF4.0: liftDir and dragDir SIZE (not direction) of vector changes forceCoeffs results MBttR OpenFOAM Running, Solving & CFD 3 July 18, 2016 07:25
liftDir and dragDir for multi elemet airfoils s.m OpenFOAM Running, Solving & CFD 1 May 15, 2015 14:28


All times are GMT -4. The time now is 03:18.