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-   -   Looking for inlet patch example (http://www.cfd-online.com/Forums/openfoam-solving/58826-looking-inlet-patch-example.html)

reimund June 8, 2008 17:04

Hello, I tried to follow the
 
Hello,
I tried to follow the free surface (interFoam) tutorial at www.tfd.chalmers.se/~hani/kurser/OF_phD_2007/HassanHemida/Hassan_Hemida_VOF.pdf

Unfortunately, after giving the 0/gamma file, the tutorial says "We should also change by the same way the dictionaries U and pd." I failed with my attempts to setup U and pd at the inlet patch:
"Courant Number mean: 120.443 max: 2988.99
Floating point exception (core dumped)"

Could you tell me how I have to set up the inlet patch, or where to download a complete, similar case?

Thanks
Reimund

ngj June 9, 2008 08:49

Hi Reimund Please upload th
 
Hi Reimund

Please upload the case here, and I will take a look at it. Alternatively you can use my email.

Best regards,

Niels

reimund June 9, 2008 17:46

Niels, thank you for offering
 
Niels, thank you for offering to look into the case.

I have solved part of the problem, because I initialized the gamma field by mistake different from what the tutorial suggested.

Still I don't understand why the stability of the solution depends on the initial conditions. Of course this can happen for nonlinear problems, but can the stability depend on the initial distribution of the two phases?

I'll do more tests and then upload a representative case towards the end of the week.

Thanks
Reimund

reimund June 10, 2008 12:52

So, here is how I reproduced H
 
So, here is how I reproduced Hassans tutorial case. Maybe some Openfoam beginner like me will find the complete set of files useful. I hope they are correct.
http://www.cfd-online.com/OpenFOAM_D...hment_icon.gif bottleFill.tgz
Of course, you are more than welcome to point out mistakes.

Run the case as:

tar xzf bottleFill.tgz
cd bottleFill
make

reimund June 10, 2008 16:31

After I think I have been succ
 
After I think I have been successful with the bottle case, I wanted to simulate fluid streaming over an obstacle:
http://www.cfd-online.com/OpenFOAM_D...ges/1/7976.png

Strangely in the air a region with ~50 times the inlet velocity (see U arrows) develops. Here I would need help again to understand what's going on.

If I plot the velocity magnitude:
http://www.cfd-online.com/OpenFOAM_D...ges/1/7977.png
it seems that much more water enters at the inlet(right) than leaves at the outlet (left above the quarter circle). How can this happen?

Here is again the complete input files:
http://www.cfd-online.com/OpenFOAM_D...hment_icon.gif stream.tgz

Reimund

reimund June 10, 2008 18:25

Here is a short explanation of
 
Here is a short explanation of the figures in the previous post, because the figure captions haven't been shown:

Both figures are taken at simulation time T=4s.

The first picture shows a cutplane of gamma (red=water, blue=air). The box protuding to the right is an inlet with U=(-0.1 0 0) m/s
Additionally U vectors are shown. These are as high as |U|~4.9 m/s above the water (see color scale), although the inlet velocity is only |U|=0.1 m/s, which is why the U vectors in the water are hardly visible.

The second picture simply shows a cutplane of |U| from |U|=0.0 ... 0.2 m/s.

Reimund


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