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-   -   How do you set up a porous region (http://www.cfd-online.com/Forums/star-ccm/77396-how-do-you-set-up-porous-region.html)

charltonjames June 22, 2010 08:02

How do you set up a porous region
 
Hi,

Im a little confused on how to correctly set up a porous region. I know how to create a porous region. But im confused on what interface i should use (porous baffle?), Also how do you calibrate the settings - i.e. to have a 50/50 and 70/30 porous region? Any advice would be appreciated.

regards

James

Maddin June 25, 2010 03:11

Read the manual.
It's very simple! Maybe you have to read the expression more than one time but with a little excel sheet you can set the pressure drop you need.

charltonjames June 29, 2010 11:17

Thanks Maddin, but by the manual, do you mean the help files?

I've looked there and no luck.

Any chance you could expand you answer

Maddin June 29, 2010 11:20

No the help files are only a "little" manual.
You should have some pdf-files in your ccm directory.
2000 pages strong... there you find all you need!

charltonjames June 29, 2010 11:27

ah...... i didnt know this existed. Thanks maddin.... this could answer several of my questions!!! (i hope)

niazaliahmed July 5, 2010 09:00

Re:Porous
 
There is a tutorial called Porous Flow. Go to Help>Training Guide. You may use an In-Place interface too.

charltonjames July 5, 2010 09:19

Thanks Niazaliahmed - I am using In-place interfaces now. I have a volume mesh and porous region. I just dont know what to do then - i.e. in the physics values in the porous region. I see there is a porosity setting (constant) which as default is set at one. I've tried changing this value to numerous values between 0 - 1.0 but nothing seems to work.

- I have tried the tutorial

If i apply the same process - i.e. Axisymetric Tensor; and random Pi and Pv values i do get a result. But i cannot validate this process or values or the accuracy of the given results.

Any further suggestions would be gratefully appreciated.

Vinicius July 5, 2010 12:11

The value of porosity just have effect when you are running unsteady simulations, if you are running steady, just set the Porous Inertial Resistance and Viscous Resistance.

charltonjames July 5, 2010 12:15

@Vinicius - Thank you. Thats fine. So i guess the next question is which Tensor you use? Following this i need to establish accepted values for initial and viscous resistance for trees.

famerfamer July 6, 2011 18:39

Hey James,

Given a geometry, how to create a porous region from it? Thank.

charltonjames July 6, 2011 18:44

Sorry, i dont understand you question.

Scibor79 July 7, 2011 06:54

Quote:

Originally Posted by charltonjames (Post 265788)
@Vinicius - Thank you. Thats fine. So i guess the next question is which Tensor you use? Following this i need to establish accepted values for initial and viscous resistance for trees.

Hi James

You've to choose the tensor according the flow direction in the porous region and its geometric characteristic.
you have to know if the porous region is isotropic un-isotropic, axial-symmetric etc.
For Inertial and Viscous resistance values you must have a characteristic curve (velocity/DP or similar) of the considered material.
If you need further help please describe your problem in detailed way

by

famerfamer July 15, 2011 15:15

Quote:

Originally Posted by charltonjames (Post 315021)
Sorry, i dont understand you question.

I mean do you know how to create a porous region including boundary and interface? Currently I have three parts vertically connected to each other, say A, B and C. B is the porous region which is sandwiched by A&C.

I just have no idea how to set B as a porous region and what parameters I need although I've read through that porous region tutorial...

Any help would be appreciated.

famerfamer August 13, 2011 19:29

Quote:

Originally Posted by Scibor79 (Post 315097)
Hi James

You've to choose the tensor according the flow direction in the porous region and its geometric characteristic.
you have to know if the porous region is isotropic un-isotropic, axial-symmetric etc.
For Inertial and Viscous resistance values you must have a characteristic curve (velocity/DP or similar) of the considered material.
If you need further help please describe your problem in detailed way

by

Can I calculate those two resistance values based on the equation the tutorial provides? Thanks.


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