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

Obtaining velocities at specific plane

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

Like Tree1Likes
  • 1 Post By tomf

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 14, 2018, 04:11
Post Obtaining velocities at specific plane
  #1
New Member
 
Martin Rønnov Andersen
Join Date: Oct 2018
Location: Aalborg, Denmark
Posts: 9
Rep Power: 4
Skymaas is on a distinguished road
Hey guys,


I am fairly new to openFOAM so bear with me on this:

In this study, I will be trying the find the uniformity index after an expansion and in order to calculate this, i need to know the velocities after the guide vanes(See attached picture).
I have tried to create a plane just after the guide vanes in Pointwise, which did not work. Then i tried using createPatch, but this did not work either.
Can anyone point me in the direction of how to achieve the velocities at a specific plane, after the guide vanes?
Attached Images
File Type: png Case.png (8.9 KB, 11 views)
Skymaas is offline   Reply With Quote

Old   November 15, 2018, 06:18
Default
  #2
Senior Member
 
Tom Fahner
Join Date: Mar 2009
Location: Breda, Netherlands
Posts: 564
Rep Power: 22
tomf will become famous soon enough
Send a message via MSN to tomf Send a message via Skype™ to tomf
Hi,

Working with the surfaces functionObject, something like the following, could work if you make an stl of the plane that you want to look for the velocities. You should get a high enough resolution on this stl.

Code:
    velocities_on_plane
    {
        type            surfaces;
        functionObjectLibs ("libsampling.so");
        writeControl   writeTime;

        surfaceFormat   vtk;
        fields          (U);

        interpolationScheme cellPoint;

        surfaces
        (      
            Plane
            {
                type            sampledTriSurfaceMesh;
                surface         Plane.stl;
                source          cells;
                interpolate     true;
            }       
        );
    }
ginop likes this.
tomf is offline   Reply With Quote

Old   November 16, 2018, 04:10
Default
  #3
New Member
 
Martin Rønnov Andersen
Join Date: Oct 2018
Location: Aalborg, Denmark
Posts: 9
Rep Power: 4
Skymaas is on a distinguished road
Hi tomf,


Thanks for your response!
How is one going to include a STL. file in the main geometry?
Skymaas is offline   Reply With Quote

Old   November 16, 2018, 04:33
Default
  #4
Senior Member
 
Tom Fahner
Join Date: Mar 2009
Location: Breda, Netherlands
Posts: 564
Rep Power: 22
tomf will become famous soon enough
Send a message via MSN to tomf Send a message via Skype™ to tomf
Hi

You do not do it like that. Just place a separate plane.stl into a folder called constant/triSurface/ like you would for making a mesh using snappyHexMesh. This plane.stl you have to create separately. I do not know what software you have available, but there should be multiple solutions to this. OpenFOAM will interpolate to this plane.

Hope this helps.
Cheers,
Tom
tomf is offline   Reply With Quote

Old   January 1, 2019, 06:42
Default
  #5
Senior Member
 
Mark Olesen
Join Date: Mar 2009
Location: http://olesenm.github.io/
Posts: 1,103
Rep Power: 28
olesen will become famous soon enougholesen will become famous soon enough
Quote:
Originally Posted by Skymaas View Post
Hey guys,
I am fairly new to openFOAM so bear with me on this:

In this study, I will be trying the find the uniformity index after an expansion and in order to calculate this, i need to know the velocities after the guide vane.
It is actually a bit easier than that. Uniformity Index is part of surface field functions in 1806 and later - without you needing to write any code.
The plane can either be a regular cutting plane, or from an stl, etc via a distanceSurface with distance = 0.
The latter can be rather important to obtain proper sampling per cell. There is a small example in the tutorials (compressible/rhoSimpleFoam/squareBend) that you can work from.
olesen is offline   Reply With Quote

Reply

Tags
guide, index, plane, uniformity, vanes

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
Simple piston movement in cylinder- fluid models arun1994 CFX 4 July 8, 2016 03:54
Sign of massflow across a plane Chander CFX 6 June 14, 2012 04:36
error message cuteapathy CFX 14 March 20, 2012 07:45
Problem with Sampling plane Chander CFX 10 February 20, 2012 17:57
Mixing plane geometry definition Hbet FLUENT 0 January 18, 2002 08:16


All times are GMT -4. The time now is 18:02.