[Paraview] Finding volume enclosed by a contour.

Sun Mar 5 13:52:40 EST 2017

I was trying IntegrateVaraiables with OpenFoam data last week and it seemed to give the areas OK, though the data had been converted to EnSight format- might be worth a try?

Ron fowler

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From: ParaView [paraview-bounces at paraview.org] on behalf of Felipe Bordeu [felipebordeu at gmail.com]
Sent: 05 March 2017 09:27
Cc: paraview
Subject: Re: [Paraview] Finding volume enclosed by a contour.

The volume is nothing more that the integral of one (1). So make a calculator with a new variable named "rho" and with the value 1 then apply the intégrate variable filter to compute the volume.

Be careful no to have bars in your mesh, they will also contribute to the volume calculation.

In general you must filter your mesh by dimensionality (only 3D cell or only 2D...)

Hope it helps

Felipe

Le 4 mars 2017 7:46 PM, "Gallagher, Timothy P" <tim.gallagher at gatech.edu<mailto:tim.gallagher at gatech.edu>> a écrit :

I was suggesting trying a pipeline like:

OpenFOAM Reader -> Threshold -> IntegrateVariables -> IntegrateVariables

So your second IV filter is applied to the first IV filter.

Again, no idea if that will help. Hopefully somebody else can come along and give you a solution.

Tim

________________________________
From: Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>
Sent: Saturday, March 4, 2017 1:44 PM
To: Gallagher, Timothy P; paraview at paraview.org<mailto:paraview at paraview.org>
Subject: RE: Finding volume enclosed by a contour.

Hi Tim;

Yes I do think so it is somehow related to the OpenFOAM reader. I just tried a tutorial case from the CFD package and I still have the same data set with no additional data related to the volume/ area/ length.

I am not sure if I understood your idea right, do you mean apply integrateVariables twice on the same threshold data set?

“Sorry, I tried!”

No worries this has been a long standing problem for my work. I am really happy that you shared your ideas with me.

Saideep

From: Gallagher, Timothy P [mailto:tim.gallagher at gatech.edu<mailto:tim.gallagher at gatech.edu>]
Sent: 04 March 2017 18:07
To: Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>; paraview at paraview.org<mailto:paraview at paraview.org>
Subject: Re: Finding volume enclosed by a contour.

Hmmm, interesting. It must be a function of the type of data from the OpenFOAM reader and I am unfamiliar with that reader.

All of my datasets are structured and behave the way I mentioned earlier. I'm not sure how to get the volume from the dataset you have.

Somebody else will have to chime in on this one. Just out of curiosity, if you IntegrateVariables again, does it condense the data into a single set of values? (That's a totally random guess -- maybe the first IntegrateVariables is coming up with the cell-averaged values from an unstructured dataset, and the second would do the integral of all the cell-averages).

Sorry, I tried!

Tim

________________________________

From: Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>
Sent: Saturday, March 4, 2017 1:00 PM
To: Gallagher, Timothy P; paraview at paraview.org<mailto:paraview at paraview.org>
Subject: RE: Finding volume enclosed by a contour.

Tim,

I did try to vary from pointData to cellData but I see the same fields present. That is, I see no additional field being added.

Attached is a screenshot (all the data from U are the variables being computed from my solver). I tried it over 4.x and 5.x versions of paraview so, I guess I am doing something wrong.

Saideep

From: Gallagher, Timothy P [mailto:tim.gallagher at gatech.edu]
Sent: 04 March 2017 17:36
To: Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>; paraview at paraview.org<mailto:paraview at paraview.org>
Subject: Re: Finding volume enclosed by a contour.

The IntegrateVariables filter creates a spreadsheet of PointData (or CellData, depending on where your data is stored in the filter just before IntegrateVariables) with the integral of your data over the volume/area/length depending on if it is 3D/2D/1D data respectively.

It also adds a field to the CellData array that will be Volume/Area/Length respectively.

My guess is if you aren't seeing it immediately it is because you are looking at the PointData array and not the CellData array. In the SpreadSheetView that opens up, change the Attribute dropdown from Point Data to Cell Data.

Also, as a note -- the values for your variables (pressure, velocity, whatever) are multiplied by the length scale, so if you want the average value in the domain, you need to divide it by the length scale.

Tim

________________________________

From: Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>
Sent: Saturday, March 4, 2017 12:30 PM
To: Gallagher, Timothy P; paraview at paraview.org<mailto:paraview at paraview.org>
Subject: RE: Finding volume enclosed by a contour.

Thanks Tim;

I could precisely extract the bubble using the threshold filter as you said (attached picture).

Coming to the 2nd step: I applied the integrate variables filter on the threshold data but I get the general data set values within individual cells like the computed velocity, pressure, etc….

How do I integrate the the region in space to find the enclosed volume?

Sorry, if it’s a basic question.

Saideep

From: Gallagher, Timothy P [mailto:tim.gallagher at gatech.edu]
Sent: 04 March 2017 17:09
To: Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>; paraview at paraview.org<mailto:paraview at paraview.org>
Subject: Re: Finding volume enclosed by a contour.

Your best bet would be to use the Threshold filter to extract the region where the scalar is greater (or less than) 0.5 and then use the IntegrateVariables filter on the Threshold.

It's not entirely clear your exact pipeline, but it sounds like you are using the IntegrateVariables filter on the Contour, which would give you the surface area of the region instead.

Tim

________________________________

From: ParaView <paraview-bounces at paraview.org<mailto:paraview-bounces at paraview.org>> on behalf of Saideep Pavuluri <Saideep.Pavuluri at pet.hw.ac.uk<mailto:Saideep.Pavuluri at pet.hw.ac.uk>>
Sent: Saturday, March 4, 2017 11:36 AM
To: paraview at paraview.org<mailto:paraview at paraview.org>
Subject: [Paraview] Finding volume enclosed by a contour.

Hi guys;

I am using a numerical method (Volume of fluid, just for information) to look at the breaking of a bubble in a micro-channel. Attached picture.

As mostly, the bubbles are of uniform size, I would like to know the volume of any one bubble formed.

The bubble is represented by a scalar data set represented by 1 and bounded by the same data set with values 0.

I think to clip the region enclosing one bubble and draw a contour where the scalar value is 0.5. Now, I tried the integrate variables filter but I did not find a data representing the volume.  Any idea how can I get the volume enclosed by this contour?

Any help appreciated.

Thanks;

SaiD

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