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-   -   How to plot flow rate over time with Paraview (http://www.cfd-online.com/Forums/openfoam-paraview/66874-how-plot-flow-rate-over-time-paraview.html)

sekunda July 27, 2009 11:02

How to plot flow rate over time with Paraview
 
Hello everybody, I already searched for a similar topic, but I couldn't find it.
I guess my question about Paraview (3.4.0, Win version) is rather simple for you, but I didn't find any tip about it neither on the web.

I am dealing with a fluid-structure interaction problem for hemodynamics. First step of my work is a fluid flow in a straight tube. I imported in Paraview a *.case file containing pressure, velocity and displacement data of every node of a mesh over 100 time steps. Now I have to plot pressure and flow rate (volume per second) over time for several sections of the tube. How can I do it?

I used "Slice" filter to select my sections of interest, but I don't understand how filters like "Integrate variables" or "Plot ... over time" work.

Can anybody help me (even with links to useful online tutorials, for example)?

Thanks a lot
Best regards

maysmech October 23, 2010 14:39

I have same problem in ParaView 3.8
------------

Dear Foamers,

How can i calculate mass flow rate of a surface which its velocity profile is available (by using paraView calculator)?

siddharameshwara December 15, 2010 07:37

Quote:

Originally Posted by sekunda (Post 224292)
Hello everybody, I already searched for a similar topic, but I couldn't find it.
I guess my question about Paraview (3.4.0, Win version) is rather simple for you, but I didn't find any tip about it neither on the web.

I am dealing with a fluid-structure interaction problem for hemodynamics. First step of my work is a fluid flow in a straight tube. I imported in Paraview a *.case file containing pressure, velocity and displacement data of every node of a mesh over 100 time steps. Now I have to plot pressure and flow rate (volume per second) over time for several sections of the tube. How can I do it?

I used "Slice" filter to select my sections of interest, but I don't understand how filters like "Integrate variables" or "Plot ... over time" work.

Can anybody help me (even with links to useful online tutorials, for example)?

Thanks a lot
Best regards

#


Hello,

step 1:In filters--->alphabets you select calculator option.

and then a block will be opened in that you select scalars---->U_X or U_Y depending on the direction you want. and name it in the Result array name as :)flow rate:) and then click apply.

step 2: and the n select filters---->alphabets----> integrate variables option.

step 3:It will display one window in that you select the variable name you have given :)flowrate:)

step 4:Now, filters----->alphabets---->plot selection over time

now click the copy active selction option and then press apply.

vinaynitrkl May 2, 2011 08:31

Plotting an average value of pressure Vs Time
 
I want to plot a graph of average value of pressure at certain height Vs Time of a 3D column in Paraview. I am a newbie to paraview. Couldn't find any relevant info on net and in paraview tutorial.

Can anyone please help me with this?

giovanni10 November 1, 2011 08:46

Quote:

Originally Posted by siddharameshwara (Post 287523)
#


Hello,

step 1:In filters--->alphabets you select calculator option.

and then a block will be opened in that you select scalars---->U_X or U_Y depending on the direction you want. and name it in the Result array name as :)flow rate:) and then click apply.

step 2: and the n select filters---->alphabets----> integrate variables option.

step 3:It will display one window in that you select the variable name you have given :)flowrate:)

step 4:Now, filters----->alphabets---->plot selection over time

now click the copy active selction option and then press apply.


I have a 2D cavity (2Pi X 2Pi) with periodic boundary conditions in both x and y directions. I have already found the kinetic energy {(Ux²+Uy²)/2 } for each time step.
At the moment, I want to find the mean kinetic energy for each time step and plot kinetic energy versus time.
I was thinking of declaring in calculator a variable Ekinetic/(2Pi²) and and select integrate variables option. Then, plot selection over time.
Is it correct?
Thanks in advance!

AlmostSurelyRob November 18, 2011 05:42

Quote:

Originally Posted by siddharameshwara (Post 287523)
#

step 1:In filters--->alphabets you select calculator option.

and then a block will be opened in that you select scalars---->U_X or U_Y depending on the direction you want. and name it in the Result array name as :)flow rate:) and then click apply.

step 2: and the n select filters---->alphabets----> integrate variables option.

step 3:It will display one window in that you select the variable name you have given :)flowrate:)

step 4:Now, filters----->alphabets---->plot selection over time

now click the copy active selction option and then press apply.

I would just like to add one comment. For the flow rate, above procedure works well as for ParaView 3.12. There is one more step though between 3 and 4

Step 3' Visualise your integrate variables in a 3D view and select in via Select Points Through

Step 4 Apply your Plot selection over time

Also in case you were like me and wanted to plot an integral of a scalar over time rather than flow rates bear in mind that you still HAVE to use the Calculator filter. I am not sure why this is so, but if I was doing integrate variables on my raw scalar fields the Plot Over Time filter wouldn't work. I guess it has something to do with the fact that the first variable in my Integrate Variable was velocity.

After applying the Calculator filter and just retyping my scalar as "Result" I got what I wanted.

Thanks!

sto16 December 15, 2011 06:25

selection plot over time
 
hey...

i have a 2d simulation of a turbulent 2 species flow in reactingFoam.

Now i want to plot the change of concentration of the species at one point on the bottom line ("wall") over the time.
I tried the steps u explained before and I managed to select points and cells - but when i click on "plot selection over time" there is always an error-message with several entries:

"warning: in /build/buildd /paraview-3.6.2/VTK/Common/vtkDataArrayTemplate.txx, line 450
vtkIdTypeArray (0xd1c7248): Input and Output array data types do not match"


do u have an idea how to solve this problem.

Is there a problem because of the boundary conditions at the wall?

But even when i choose a point some distance away from the wall, the error comes again.

:confused:

sto16 December 16, 2011 03:46

ok...
i managed to plot several informations (RowData: p, U, T, ...) over time with a finer mesh and selecting cells, which do not belong to the wall, by entering the location manually.

unfortunatelly i can not plot the concentration over time.


does anybody have an idea what is the reason for this problem and how to solve it?!?


greetz and thanks...

openfoammaofnepo July 18, 2014 05:31

Dear Robert,

Thank you for your comments. For your Step 3', I am not sure the underlying purpose. When I apply the Integrate Variable filter, I will have a separate window, actually it is a table where the integral values are listed there. Here why the 3D visulization is needed here for plotting the selection over time?

OFFO

AlmostSurelyRob July 18, 2014 11:24

The reason for doing 3' is to be able to do 4. In order to run "Plot Selection over Time" you need something to be selected and as far as I know you cannot just select it in "Pipeline Browser". It must be selected from one of the views. 3D is one possibility, but you can also select a tuple from your table view and then run "Plot selection over time" which is perhaps more intuitive, but I wasn't aware of this possibility at the time.

So to summarise 3' is optional. You just cannot select Integrate Variables from the "Pipeline Browser" must be a view, either "Table View" or "3D view" but you must select something. In 3D view Integrate Variables is represented as a point in Table View it's a tuple.

Hope that helps.

openfoammaofnepo July 18, 2014 11:28

Thank you. I found that when I complete the filter "integrate the variables", I can click the table , and then click the copy active selction option and then press apply. It seems working. Now my paraview is running and I will see it can indeed give me the results I want. Which version did you use? Thank you.

AlmostSurelyRob July 20, 2014 06:25

I am on the latest ParaView. 4.1 I think, but these posts were probably related to 3.x. I would say that the only counter-intuitive thing is that a selection of an object from Pipeline Browser + Plot Selection Over Time (PSOT), doesn't work. I guess this has to do with the way PSOT is working - you have to select something from an active view rather than browsers.

openfoammaofnepo July 20, 2014 15:24

Dear Robert,

Thank you for your reply. I use Paraview 3.98.1, and what you mentioned worked. But now I have a problem. When I use the above procedures, the paraview will work for a long time since my data is very large. Sometimes paraview console will terminate automatically. Did you have this similar problem when you did the above procedures?

Thank you very much.
OFFO


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