CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

velocity BC for pourous wall (pressure dependendend darcy law)

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 19, 2017, 10:40
Default velocity BC for pourous wall (pressure dependendend darcy law)
  #1
New Member
 
Stefan
Join Date: Oct 2015
Posts: 24
Rep Power: 10
StefanW is on a distinguished road
Dear FOAMers,

i wanna investigate a dead end pipe with some porous areas at the wall.
The porosity variates along the axis, so I will divide the wall in different parts and each part sould get an individual BC depending on the local porosity.
At the inlet of the pipe I will define a pressure BC. Simulation will be steady-state.

My goal is to analyze the averaged leakage for each part of the wall.
I don't wanna simulate the outside of the pipe. I just wanan look at the massflow through the porous wall(s) (which will be treated like an outlet patch).
The fluid is incompressible so i get the massflow with u*rho*area of the wall.

Therefore I'm looking for a velocity BC for porous walls which follows darcys law.

I thought of setting atm pressure at the wall as p-BC.
The velocity BC should calculate the preassure drop between in and outside the pipe (according to the results of the flow field inside) and use a manually given permeability factor k, to calculate the velocity.

Simplified
u=deltaP*k (normal to the wall)
u=0 (not normal to the wall => there should be shearing)

in the end it is the exact oppposite of the slip condition:
There, the normal component is zero (sliding). It would be a wall (no fluxes can pass) but there is finally no shearing based on the fact that we assume that there are no viscous effect.


I had a look through the provided BC of OpenFOAM but could not find a suitable one for my problem. I also searched in the forum - no success.

May some of you could help me out which one i have to use,
or, in case there isn't such a BC, which one shound be suitable for start programming by myself.

Thanks a lot

Stefan
StefanW is offline   Reply With Quote

Old   May 29, 2017, 07:53
Default BC pourous wall
  #2
New Member
 
Stefan
Join Date: Oct 2015
Posts: 24
Rep Power: 10
StefanW is on a distinguished road
Hi again,

nobody got an idea according this problem?

It would help a lot.

Thank you.
StefanW is offline   Reply With Quote

Reply

Tags
boundaries condition, darcy's law, permeable wall, porous walls, velocity boundary

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wind tunnel Boundary Conditions in Fluent metmet FLUENT 6 October 30, 2019 12:23
Centrifugal fan j0hnny CFX 13 October 1, 2019 13:55
Centrifugal fan-reverse flow in outlet lesds to a mass in flow field xiexing CFX 3 March 29, 2017 10:00
Variables Definition in CFX Solver 5.6 R P CFX 2 October 26, 2004 02:13
how to print the results from CFX-4.2 cfd_99 Main CFD Forum 5 June 21, 1999 09:23


All times are GMT -4. The time now is 01:10.