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New Code Saturne tutorial online

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16 years 1 week ago #2826 by Claus
Replied by Claus on topic Re:New Code Saturne tutorial online
When I change the pressure from 1kPa to 0.7kPa in my MachCAD doc. I get a theoretical exit speed of 32.142[m/s] so the ballparking of 33[m/s] seems ok.

About the flow rate from the flowmeter: well I'm not sure what relative density to use, because I don't know the exact composition of the natural gas we use here - it actually differs quite a lot from place to place so pure methane was used. Second, it is taken from a table at 20c or 25c (I forget right now) so that has an impact as well.

Another thing that has a small impact, is the shape of the modeled nozzle, it doesn't entirely correspond to the real world one.

All in all - lots of variables :laugh:

I also tried using compressibility earlier,but failed - maybe *SOMEONE* (hint) could give us an example.

I've gotten an older copy of the Crane doc. I'll have a look at it - maybe I'll be inclined to buy it later.

Oh yeah, feel free to post the .hdf, I'd like to see what kind of mesh you created.

Code_Aster release : STA11.4 on OpenSUSE 12.3 64 bits - EDF/Intel version
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16 years 1 week ago #2829 by Robin Borland
Replied by Robin Borland on topic Re:New Code Saturne tutorial online
Claus,

My files uploaded are located here:

www.caelinux.org/wiki/index.php/Special:Imagelist

A few notes on these:

1. It seems that the previous simulations ( yours and mine) are off on the density - we both inadvertantly used SG instead of density in Kg/M^3 - per the Crane book, a typical value for a typical natural gas composition is 0.8034 Kg/M^3

2. I used 1.25 *10^-5 for the absolute viscosity

3. My mesh is coarse - 0.5mm tet mesh - it could be finer, but I don't have a lot of computer horsepower at present, or I would refine it.

4. The simulations done are close to your real world results - any differences are probably due to mesh density ( accuracy), and geometry differences between what was tested and what was modelled.

5. The updated Mathcad file with the density correction is attached to this post, I also added the Re number check.

Again - thanks for your efforts on this, I have found it useful to be able to compare text book predictions, with what CFD results are vs. your real world tests.

Regards
Robin

PS: I did get a sample file from Code Saturne Support of a compressibility example, I did not look at it yet in any great amount of detail - it uses a mesh file format that I am not familiar with, but you can look at the extra Fortran files that they used -
I will post it to the Wiki also in case anyone else wants to look at it.<br /><br />Post edited by: Robin Borland, at: 2009/04/22 17:16
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16 years 1 week ago #2830 by Robin Borland
Replied by Robin Borland on topic Re:New Code Saturne tutorial online
Matchcad file attached

Attachment Orifice_Flow_gas-a0082d9355d9347bead7ee7e6b1a7dee.rar not found

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16 years 1 week ago #2844 by Claus
Replied by Claus on topic Re:New Code Saturne tutorial online
Thanks for your reply - Unfortunately I don't have the time atm. to update the wiki nor rerun the simulation, maybe later on I'll get it done - In the meantime I'll link to this thread on the wiki so people can view the discussion.

Code_Aster release : STA11.4 on OpenSUSE 12.3 64 bits - EDF/Intel version
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14 years 9 months ago #4483 by florante
Replied by florante on topic Re:New Code Saturne tutorial online
Claus,

I like your tutorial but I found it a bit pain reading it in wiki. So I did a presentation out of it and I think this is more readable/printable

See attached.

thanks

Post edited by: florante, at: 2010/07/27 18:44<br /><br />Post edited by: florante, at: 2010/07/27 19:05
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14 years 9 months ago #4484 by florante
Replied by florante on topic Re:New Code Saturne tutorial online
[file] florante wrote:

Claus,

I like your tutorial but I found it a bit pain reading it in wiki. So I did a presentation out of it and I think this is more readable/printable

See attached.

thanks

Post edited by: florante, at: 2010/07/27 18:44&lt;br /&gt;&lt;br /&gt;Post edited by: florante, at: 2010/07/27 19:05

<br /><br />Post edited by: florante, at: 2010/07/27 19:13
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