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

how should we define the CofR in forceCoeffs function?

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

Like Tree1Likes
  • 1 Post By Bloerb

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 9, 2022, 15:05
Default how should we define the CofR in forceCoeffs function?
  #1
New Member
 
Basar H.Ibrahim
Join Date: Sep 2021
Posts: 7
Rep Power: 4
Pasar is on a distinguished road
Hi, everyone!
In the controlDict you can use a function that is defined to give force on the body I want to ask a question about CofR,
I know that CofR is a center of rotation.
if the Body moves down, how should I set the Cof, still keep a fixed value? Can anyone help me solve the question?

PHP Code:
    forces
    
{
        
type            forces;
        
libs            (forces);
        
patches         (body);
        
rhoInf          997;
        
log             on;
        
writeControl    timeStep;
        
writeInterval   1;
        
CofR            (a b c);

    } 
Pasar is offline   Reply With Quote

Old   March 9, 2022, 15:10
Default
  #2
Senior Member
 
Join Date: Sep 2013
Posts: 353
Rep Power: 20
Bloerb will become famous soon enough
It's the point around which your torque will be calculated. Hence if you are only interested in the forces enter whatever maybe (0 0 0). You can calculate the center of gravity of an stl file with the tool surfaceInertia. So depending on your problem you might want to use that.


But if you enter (0 0 0) you can obviously always transform that by hand into another point since you will have the torque and force as output.
Pasar likes this.
Bloerb is offline   Reply With Quote

Old   March 9, 2022, 16:05
Default
  #3
New Member
 
Basar H.Ibrahim
Join Date: Sep 2021
Posts: 7
Rep Power: 4
Pasar is on a distinguished road
Quote:
Originally Posted by Bloerb View Post
It's the point around which your torque will be calculated. Hence if you are only interested in the forces enter whatever maybe (0 0 0). You can calculate the center of gravity of an stl file with the tool surfaceInertia. So depending on your problem you might want to use that.


But if you enter (0 0 0) you can obviously always transform that by hand into another point since you will have the torque and force as output.
Thank you Bloerb for your explanation.
I have a body falls down into the water, so
I want to calculate the pressure of water on the body.
Pasar is offline   Reply With Quote

Reply

Tags
controldict., functionobject

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
[mesh manipulation] refineMesh Error mohsen.boojari OpenFOAM Meshing & Mesh Conversion 3 March 1, 2018 22:07
An odd ERROR mdakbari Fluent UDF and Scheme Programming 7 April 4, 2016 04:30
[snappyHexMesh] How to define to right point for locationInMesh Mirage12 OpenFOAM Meshing & Mesh Conversion 7 March 13, 2016 14:07
[blockMesh] Axisymmetrical mesh Rasmus Gjesing (Gjesing) OpenFOAM Meshing & Mesh Conversion 10 April 2, 2007 14:00
REAL GAS UDF brian FLUENT 6 September 11, 2006 08:23


All times are GMT -4. The time now is 04:13.