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

How to get stress on a wall from the wind

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 1, 2020, 07:29
Default How to get force on a wall from the wind
  #1
New Member
 
LE GARREC Vincent
Join Date: Aug 2020
Posts: 3
Rep Power: 5
bansan is on a distinguished road
Hi,


I run the example windAroundBuildings. I now have the U (x, y, z) and p.


My question is simple : how can I have the pressure on the wall ? I try to use the x projection of the pressure. But on the wall, the pressure is vertical so I don't have any horizontal effort.


Can you explain me how can I compute the pressure on the wall ?


I'm civil engineering, not a physician so maybe it's a formula I don't know.


Thanks for any advice,


Vincent
Attached Images
File Type: jpg p.jpg (97.4 KB, 6 views)
File Type: jpg u.jpg (102.5 KB, 6 views)

Last edited by bansan; August 3, 2020 at 05:54. Reason: It's force I need more than stress
bansan is offline   Reply With Quote

Old   August 3, 2020, 03:55
Default
  #2
New Member
 
Vignesh S P
Join Date: Jul 2018
Location: Coimbatore, Tamil Nadu, India
Posts: 17
Rep Power: 7
VigneshSP is on a distinguished road
Hi bansan,
I would recommend you to use "forces" function object and you can get the force on the patches directly and write it as a field.

for Openfoam v2006 : https://www.openfoam.com/documentati...es-forces.html

for Openfoam V8 :
https://cpp.openfoam.org/v8/classFoa...1_1forces.html

example video:
https://youtu.be/LFn7ti4nCm8
VigneshSP is offline   Reply With Quote

Old   August 3, 2020, 05:56
Default
  #3
New Member
 
LE GARREC Vincent
Join Date: Aug 2020
Posts: 3
Rep Power: 5
bansan is on a distinguished road
Thanks, it's almost what I wanted. But instead of the sum, do you know if it's possible to have the force in each node of the mesh ?
bansan is offline   Reply With Quote

Old   August 3, 2020, 08:35
Default
  #4
New Member
 
LE GARREC Vincent
Join Date: Aug 2020
Posts: 3
Rep Power: 5
bansan is on a distinguished road
A found a trick to get force at every point.

In file src/functionObjects/forces/forces/forces.C, in function void Foam::functionObjects::forces::applyBins, I add

Code:
forAll(fN, i)
{
  Log << "fN, fT, fP, d : " << fN[i] << " " << fT[i] << " " << fP[i] << " " << d[i] << endl;
}
I just have to do the sum (fN+fT+fP) manually.

It's a hack but that do the job. Thanks again for your help.
bansan is offline   Reply With Quote

Old   August 3, 2020, 08:47
Smile
  #5
New Member
 
Vignesh S P
Join Date: Jul 2018
Location: Coimbatore, Tamil Nadu, India
Posts: 17
Rep Power: 7
VigneshSP is on a distinguished road
Glad to help, best wishes
VigneshSP is offline   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
Wall shear stress for solid phase? qi.yang@polimi.it OpenFOAM Programming & Development 0 February 24, 2020 06:26
Export Wall Shear Stress Data trooken FLUENT 6 February 5, 2019 15:09
[ICEM] Export ICEM mesh to Gambit / Fluent romekr ANSYS Meshing & Geometry 1 November 26, 2011 12:11
Fluid wall shear stress Sinead Kelly (Kelly) OpenFOAM Running, Solving & CFD 2 March 30, 2011 06:41
Problems with wall shear stress. xiexiehezuo FLUENT 1 September 22, 2009 12:26


All times are GMT -4. The time now is 04:35.