CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Programming & Development

Extracing forces to implement friction in SixDoFRigidBodyMotion

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 6, 2016, 21:10
Default Extracing forces to implement friction in SixDoFRigidBodyMotion
  #1
New Member
 
Join Date: Dec 2015
Posts: 22
Rep Power: 2
toodles is on a distinguished road
Hi everyone,

I am relatively inexperienced with the code structure of OpenFoam. I have created and ran many cases; however, I have come to the point where I need to start adding functionality to the source code.

For my case, I am examining an oscillating plate that moves when induced by wave forces. I have the case running beautifully using interDyMFoam and sixDoFRigidBodyMotion solver. In addition to having linear springs and dampers, I need to be able to add a frictional effect. Basically, I want to extract the instantaneous horizontal force on the plate and multiply it by a particular coefficient to make a vertical restraining force. I feel that the perfect place to do this is within the SixDoFRigidBodyMotion class; however I am stuck on extracting the forces. I am trying to find them in the forces.C class, but I am pretty lost on how to call the forces within 6DoF.

In post processing I am writing the forces to a text file using libforces in the controlDict and have verified that they are correct. It is just a matter of being able to use them now. If anyone could provide some insight on this, I would really appreciate it.
toodles is offline   Reply With Quote

Old   April 13, 2016, 20:14
Default
  #2
New Member
 
Join Date: Dec 2015
Posts: 22
Rep Power: 2
toodles is on a distinguished road
Here is an update on this:

I feel like I am very close to getting this; however, I am absolutely stuck. I am calculating the force that I need in one class called sixDofRigidBodyMotionSolver.C and am storing this into a variable. I need to be able to read this variable in a different class, linearSpring.C, but I am having trouble knowing where to declare it so I can access it from outside the class. Is there a main code anywhere that all of the public variables are defined? I really would appreciate any help, as my mind has been going in circles for about a week.
toodles is offline   Reply With Quote

Old   May 17, 2016, 04:29
Default
  #3
Member
 
Federica Biano
Join Date: Feb 2016
Location: Genova, Italy
Posts: 38
Rep Power: 2
federicabi is on a distinguished road
Hi toodles!
I'm working on a similar case: I have to simulate a planning hull motion in a towing tank test with calm water so I need to extract the x-component of the total force acting on the hull to evaluate the vertical force that is experienced during the test in addition to the buoyancy and lift normally acting on the hull during its motion. This vertical force has to be added in the motion equation to obtain the correct motion of the hull, so I need to modify sixDoFRigidBodyMotion solver, but I don't know how. since your case is similar to mine, can you Explain how did you do that?

I appreciate you help.

Best regards

Federica
federicabi is offline   Reply With Quote

Old   May 17, 2016, 04:56
Default Nusselt number
  #4
New Member
 
Djamila Benyoycef
Join Date: May 2016
Posts: 3
Rep Power: 2
djamila77 is on a distinguished road
Hi,all

I tried to calculate the average Nusselt number with CFD; but I don't know how to do it. Only I draw The surface Nusselt Number with it.

can i get a help.

many thanks
djamila77 is offline   Reply With Quote

Old   May 17, 2016, 06:31
Default
  #5
Member
 
Federica Biano
Join Date: Feb 2016
Location: Genova, Italy
Posts: 38
Rep Power: 2
federicabi is on a distinguished road
Dear Djamila
if you have local Nusselt number you can use numerical integration. For the local calculation of Nusselt number look at Code for Nusselt number

Best regards

Federica
federicabi is offline   Reply With Quote

Reply

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
Pressure and density values to compute forces fernexda OpenFOAM Post-Processing 2 March 6, 2015 04:39
Forces for airfoil test case Martin_ OpenFOAM Running, Solving & CFD 1 July 2, 2012 11:58
friction forces icoFoam ofslcm OpenFOAM 3 April 7, 2012 10:57
FORCES don't run! C12Carbon OpenFOAM 0 September 10, 2011 07:34
Valve Forces in CFdesign Mike Clapp Main CFD Forum 3 March 8, 2001 15:09


All times are GMT -4. The time now is 14:35.