CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM

flux conservation after mesh refinement

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

LinkBack Thread Tools Display Modes
Old   August 13, 2011, 19:21
Question flux conservation after mesh refinement
New Member
Alin Anton
Join Date: Feb 2010
Location: Timisoara
Posts: 5
Rep Power: 9
aanton is on a distinguished road
Hello folks,

I am trying to understand and implement the procedure described in 5.4 of Prof. Jasak's Thesis, and on pages 143-146, for preserving the flux conservation. That is, I need to solve the pressure equation again, and obtain conservative fluxes on a new, refined mesh. I come from computer science, and I am not a CFD user, but my field of study (CiSE) has confluenced with CFD and I am stuck with some problems. I will appreciate any help, gratefully ask for it, and I appologize for possibly poor/obvious questions/solutions. Thanks .

Question 1: If i am running an unsteady simulation, and at some moment proceed to refine the mesh and map the fields (using mapFields) from the coarse mesh to the new mesh, provided that the refinement zone is not located anywhere on the inlet or outlet, do I need to worry about violating mass conservation? I am working with incompressible flows, with the pimpleFoam solver.

Question 2: From what I understood on page 236, I edited the pEqn.H from the pimpleFoam solver and simply added the two lines to the end of it that are present in the beginning of the file, for flux calculation:

phi = (fvc::interpolate(U) & mesh.Sf()) + fvc::ddtPhiCorr(rUA, U, phi);
adjustPhi(phi, U, p);

I hope these wont get scrambled by the editor. Anyway, could you please comment on this implementation? What I am trying to do is solving the pressure equation again, and afterwards obtaining conservative fluxes.

Question 3: Can I skip solving UEqn? Can I comment out all lines that modify U in UEqn.H, including relaxation, solve(), etc, and restrict the procedure to solving pEqn.H with interpolated U values? It is faster and does not modify the velocity field.

Question 4: Can I skip the PISO-SIMPLE loop, meaning that I simply call pEqn.solve() or solve(mesh.solver("pFinal"))? How bad is it? All I need is conservative fluxes not different p -> current p, along with k and nuSgs are interpolated on the new mesh.

Question 5 (last): In order to avoid unboundedness problems, do I need to actually save all the updated values for p, k, nuSgs, U along with the face flux field phi? Or all I need is pEqn.solve() , and phi?

Thank you in advance, I appreciate and value your time, help and advices. I know some questions overlap, it seems easier this way to pinpoint the issues.

I am also aware of the two following threads:

Thank you guys,
aanton is offline   Reply With Quote


conservation, flux, refinement

Thread Tools
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 On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
3D Hybrid Mesh Errors DarrenC ANSYS Meshing & Geometry 11 August 5, 2013 06:42
[ICEM] Generating Mesh for STL Car in Windtunnel Simulation tommymoose ANSYS Meshing & Geometry 48 April 15, 2013 04:24
snappyHexMesh not refining surfaces Hydro1004 OpenFOAM 3 August 29, 2012 11:56
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55
Mesh refinement and the errors. Korsh Mik CFX 0 January 11, 2006 08:07

All times are GMT -4. The time now is 19:07.