CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM Paraview & paraFoam

How to calculate the fluid flow through a surface

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

LinkBack Thread Tools Display Modes
Old   April 14, 2008, 11:23
Default Hello Foamers, i have a pro
New Member
Oliver Sommer
Join Date: Mar 2009
Posts: 12
Rep Power: 10
lynx is on a distinguished road
Hello Foamers,

i have a problem. I'm not able to calculate the fluid flow through a surface (inlet or outlet for example).

At my domain i have several inlets and outlets with different settings. ("pressureInlet", "inlet" and "fixedVelocityOutlet")
To see if paraView calculates right, i let it calulate the fluid flow at the "inlet"- and the "fixedVelocityOutlet"-patch. (one by one - not at same time). Because so i can compare the paraView result value for the fluid flow with the theoretical value which i set up through the magnitude of the surface area and the given velocity there (dV/dt=A*U). (they should be equal)

My procedure:
I clicked on "Filter" in the menu and selected "Extract Parts" by clicking on it. Then i chose my "inlet"-patch (for example) and clicked on "Accept". Now with "ExtractParts0" highlightened i clicked on "Generate a Glyph" and the velocity-vectors from this patch (surface) are shown. Last i clicked on "Integrate a Vectorfield" to yield the fluid flow through this surface. But now i get the problem. the calulated value does not match the theoretical value.

My questions are:
1)Did i anything (or all) wrong?
2)What are the units (dimension) of this value there? (my theor. fluid flow value was in [m/h] - so i calculated it to [m/s], cause foam uses [m] als length units (as i likely too)
In fact i expected a value arround 160000 m/h and paraView showed me a value arround 120.000 [???]
3)Is the "." (dot) a sign for the 1000er value or the comma for the value?

Thank you in advance for your help.
lynx is offline   Reply With Quote

Old   April 14, 2008, 14:53
Default Don't know how to do it in par
Assistant Moderator
Bernhard Gschaider
Join Date: Mar 2009
Posts: 4,017
Rep Power: 43
gschaider will become famous soon enoughgschaider will become famous soon enough
Don't know how to do it in paraview.
I usually do it with this utility:
(it should compile as posted under 1.4, if not: tell me so.) (there is a more advanced version floating around on the message board)

Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request
gschaider is offline   Reply With Quote

Old   April 18, 2008, 04:25
Default Hello!! Don't know how to d
New Member
Gabriela Bracho
Join Date: Mar 2009
Location: Valencia, Valencia, Spain
Posts: 14
Rep Power: 10
gaby is on a distinguished road

Don't know how to do it in paraview.

You can go to the discussion:

There is the application "calcMassFlow" (by Philippose Rajan), and the steps that you must follow. It works very nice.

I hope it will work for you.

gaby is offline   Reply With Quote

Old   April 19, 2008, 09:31
Default Hi Oliver, there is an easy
Johannes Baumann
Join Date: Mar 2009
Location: Baden-Wuerttemberg, Germany
Posts: 43
Rep Power: 10
johannes is on a distinguished road
Hi Oliver,

there is an easy way to calculate the volume flow in ParaView using the filter "Surface Flow".

Unfortunately, it doesn't work with standard OpenFOAM files, so you have to convert your case to VTK format first.

Then you can open the .vtk file of the patch you want to determine the flow through and apply the Surface Flow filter. It will print out the volume flow in m/s.

If you want to calculate the flow at various timesteps and are using ParaView 3.*, be sure to open the top level .vtk file (e.g. "outlet_..vtk") in a patch directory and not a timestep specific file (e.g. "outlet_10.vtk").

You may get an error regarding missing vectors when applying the filter and/or viewing timestep "0". The reason is: After converting an OpenFOAM case to VTK the first timestep does not contain any fields and thus no volume flow can be calculated. So nothing to worry about.

Best regards,
johannes is offline   Reply With Quote

Old   January 20, 2016, 12:58
Thomas Oliveira
Join Date: Apr 2015
Posts: 92
Rep Power: 4
t.oliveira is on a distinguished road
You can also try using a function object. See this post for instructions:
t.oliveira is offline   Reply With Quote


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
Calculate fluid area ivanyao OpenFOAM Running, Solving & CFD 0 March 30, 2008 11:03
Calculate fluid velocities Sergio Feitoza Main CFD Forum 1 January 10, 2007 15:06
About fluid surface jasonchang CFX 8 June 9, 2006 20:53
Non-Newtonian Fluid Flow with Free-Surface Valdemir Main CFD Forum 1 March 10, 2003 14:03
how to calculate the flow rate through a surface july Siemens 3 February 15, 2002 08:06

All times are GMT -4. The time now is 15:58.