[CFX_Beginner]

Hello guys,

I need some help to figure out the exact meaning or definition of some of the Porous Settings in a Porous Domain.

I attached a picture of my Porous Settings Tab where i highlighted the options i would like to know more about.

Thank You!

[Martin_Sz]

you can find equations in ansys help for these parameters

[CFX_Beginner]

Hi Martin,

I already checked the Ansys Help and found information to all the settings I didn't highlight in the picture. But for the ones highlighted i couldn't find anything in the Ansys Help.

[Opaque]

You may want to read the following section of the documentation

Chapter 1: Basic Solver Capability Theory | 1.8. Sources | Momentum Sources

The momentum loss through an isotropic porous region can be formulated using permeability and loss coefficients as follows:


(1–182)

where  is the permeability and  is the quadratic loss coefficient. The linear component of this source represents viscous losses and the quadratic term represents inertial losses.

Note:   may be thought of as a 'pressure gradient per dynamic head'. An engineering handbook may provide data in the form of a 'pressure drop per unit head'. To calculate , divide by the distance over which the pressure drop occurs (which could be the thickness of a perforated plate, for example).
The source may alternatively be formulated using linear and quadratic resistance coefficients, substituting two coefficients  and  as follows:


(1–183)

Unfortunately, the equations do not show up.

Hope the above helps,

[CFX_Beginner]

Hi Opaque,

first of all thanks for your answer, I really appreciate your help.

Sadly the chapter doesn't really provide the answer i was looking for.

I need to know how the permeability and the resistance loss coefficient are defined and how the influence on the modell is.

[Opaque]

I am not sure how you are reading the information in the documentation, nor what you expect.

How the porous loss is included in the momentum equations is very explicit by looking at the equations shown in the documentation. How the permeability relates to the resistance coefficients is also shown.

If you need to know how permeability of a porous medium is defined, you may need to refer to a general book on porous media, or from a quick search in the web:

https://en.wikipedia.org/wiki/Permea...arth_sciences)

or

https://en.wikipedia.org/wiki/Darcy%27s_law

Hope the above helps,

[CFX_Beginner]

Hi Opaque,

those 2 wikipedia articels were kinda what I was looking for. If such definitions just existed in Ansys Help directly it would be perfect.

[Opaque]

Glad the information helped.