|
[Sponsors] |
![]() |
![]() |
#21 |
New Member
G. D. McBain
Join Date: Apr 2010
Posts: 3
Rep Power: 16 ![]() |
Dear Gilles,
This is quite a good idea; I believe artificial compressibility may even have originally been developed as a false-transient method of enforcing incompressibility (though I don't have access to Chorin's paper at the moment). While it might be possible to adapt and re-use the infrastructure of class ddt as commonly used in the transient solvers distributed with OpenFOAM, such as laplacianFOAM, that wouldn't be necessary in this case. Instead, I presume one would really only contemplate using backward-Euler integration for the false transient, so all that would be required is to set up two lots of variables for the unknowns, e.g. add pold for the pressure, defined just like your original pressure variable. Then formulate the backward-Euler step equation for your pseudo-time, and each pseudo-timestep, solve these for the new unknowns in terms of the old and then copy the new to the old, repeating till converged within a tolerance (or whatever). Implement this as a standard C++ while-loop, inside the real time-stepping loop. (Again, there are facilities in the OpenFOAM library to support iteration, but it's by no means necessary to use them if you haven't learned them, as nothing too complicated is required here.) Hope this helps. |
|
![]() |
![]() |
![]() |
![]() |
#22 |
New Member
Stefan
Join Date: Sep 2016
Posts: 11
Rep Power: 10 ![]() |
Can anyone explain me for noobs what is artificial compressibility?
lg Stefan |
|
![]() |
![]() |
![]() |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
[blockMesh] BlockMesh FOAM warning | gaottino | OpenFOAM Meshing & Mesh Conversion | 7 | July 19, 2010 15:11 |
[Gmsh] Import problem | ARC | OpenFOAM Meshing & Mesh Conversion | 0 | February 27, 2010 11:56 |
Problem installing on Ubuntu 9.10 -> 'Cannot open : No such file or directory' | mfiandor | OpenFOAM Installation | 2 | January 25, 2010 10:50 |
[blockMesh] Axisymmetrical mesh | Rasmus Gjesing (Gjesing) | OpenFOAM Meshing & Mesh Conversion | 10 | April 2, 2007 15:00 |
[Gmsh] Import gmsh msh to Foam | adorean | OpenFOAM Meshing & Mesh Conversion | 24 | April 27, 2005 09:19 |