How to apply porosity setting?
 

Hi,


I have one porous media in my computational domain. But I face with error related to porous media. I am sure that this error is depended on setting of porous media domain. The porous domain has different options that I don't know that how to setting up those options. How can I compute these options? I am grateful that that guide me in this case or give me some ideas or useful papers/sites to solve this problem. I apply porosity setting as follows:


http://uupload.ir/files/bzdt_444444444444444444.png






http://uupload.ir/files/0nz5_44444444444.png
http://uupload.ir/files/0nz5_44444444444.png




Error is as follows:


http://uupload.ir/files/1l6_111111.png


http://uupload.ir/files/omlj_111.png

While it is possible that the porous domain is linked to the floating point error, you should read the floating point error FAQ to make sure you have the general background on the issue: https://www.cfd-online.com/Wiki/Ansy...do_about_it.3F

Looking at the timescale of your simulation (87000 s = ±1 day), I think one of your BC-settings is wrong. Possibly you only set pressures? It might help to set an initial velocity scale as initial guess to help CFX to determine the auto-timescale more accurate, or use physical timestepping.

For calculating interfacial area density and loss coefficient, there are formulae. But they depend on level of porosity. The ones valid for low porous, like .7, are not valid for highly porous medium like of value 0.95.

Similarly it depends on size of porous medium. Like 2mm thick foam behaves very different from 10mm even the 2mm was part of same parent foam.

Could you please give me link/ducument about formulae?

There are many paper.. Anyway, send me an email. muhammad.arslan@mail.bcu.ac.uk
It is better always, to look for a book/paper where they have given data of each parameter instead of calculating it by yourself.