[Paraview] ParaView Digest, Vol 64, Issue 8, Message 2

[Wei Wu]

Dear Tobias,

Many thanks for your help.

Do you think it is necessary to extract the sub-domain, on which I  
want to calculate average value, previous to using the integrate filter?

I am so sorry that I am still confused about the integrate filter. For  
example, I have a result, in which temperatures are in the range 20 ~  
39.5 degree C. After I apply the integrate filter, I got the  
temperature value is 0.00210551, which is so small. I multiply this  
value with the cell number, 23040, I got 48.5109504, which is beyond  
the range.

You did mention I have to multiply this averaged value with the  
calculated area value to produce proper values. I feel sorry that I  
don't truly understand this. In my example, the area/volume is very  
small. They are at the level 0.01/0.001. Therefore 0.00210551 times  
total area/volume cannot give a reasonable temperature either. I feel  
quite confused.

Many thanks in advance for your further help.

Regards, Wei

Quoting Tobias Froebel <tfroebel at gmx.de>:

> Hello Wei,
>
> I'm using the Integrate Filter to calculate area- and mass-averaged flow
> values in planar polydata grids (boundary surfaces) of cfd-models.
>
> It's important to convert point-data to cell-data previous to applying
> the integrate variables filter. After applying this filter you receive
> area averaged values of every cell-data. Therefore in my case you would
> have to multiply the averaged value (for example averaged temperature)
> with the although calculated area value to receive "proper" temperature
> values.
>
> I've never tried to apply the integrate filter on 3D volume data, but I
> expect volume averaged results, therefore multiplying with the volume
> value should give you more meaningful values.
>
> Tobias
>
> --
> Dipl.-Ing. Tobias Fröbel / CFD
>
> Institute for Flight Propulsion / TU Munich
>
>> Message: 2
>> Date: Wed, 5 Aug 2009 12:01:19 +0100
>> From: "Wei Wu" <wei.wu-2 at postgrad.manchester.ac.uk>
>> Subject: [Paraview] Average value on specific sub-domains
>> To: <paraview at paraview.org>
>> Message-ID:
>> 	<002401ca15bc$0fee9790$2fcbc6b0$@wu-2 at postgrad.manchester.ac.uk>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Dear all,
>>
>> I am from Manchester, UK and I am new to CFD calculations. I am  
>> using Code_Saturne(http://code-saturne.blogspot.com) /FVM method to  
>> produce data in EnSight format and then checking it in ParaView. An  
>> illustration is attached. I am working on coolant oil flow and so  
>> the picture shows a matrix of oil flow ducts. This is a 2D model  
>> with structured rectangular mesh grid, but the mesh density is not  
>> uniform.
>>
>> In order to compare with results from my lumped parameter models, I  
>> have to investigate average values of parameters (the most  
>> important one of these is temperature) on specific sub-domains, as  
>> framed out in the picture. I found a solution  
>> (http://www.paraview.org/pipermail/paraview/2008-April/007882.html)  
>> and tried the filter "integrate variables", but found the result  
>> doesn't seem to be reasonable. I guess I must did something wrong.
>>
>> I am quite interested in the extension script by python. Because my  
>> model is constructed by basic geometric elements, and the number of  
>> the elements is growing along with my progress, I am thinking about  
>> using python to obtain average values for all of the sub-domains in  
>> a loop. If I can access information of all the cells in a specific  
>> sub-domain (I can compute coordinate of these domains first),  
>> including rectangular cells' sides and areas as well as the  
>> corresponding cell values (temperature, pressure, velocity etc), I  
>> guess it is not difficult to derive average values for all of the  
>> sub-domains.
>>
>> I know a little about python and have experience on programming. I  
>> looked up ParaView Wiki, tried some python samples, but  
>> unfortunately I still don't know how to start to implement my idea.  
>> Is there a detailed API functions manual existing? Or could you  
>> please give some hints or examples to help?
>>
>> Thank you very much for your help about this.
>>
>> Best regards,
>> Wei
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