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

Tmax in reactingFoam depends on CFL-number (?)

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 20, 2011, 14:55
Default Tmax in reactingFoam depends on CFL-number (?)
  #1
New Member
 
Andras Horvath
Join Date: Mar 2009
Posts: 29
Rep Power: 17
andras is on a distinguished road
Dear Foamers,
I am using OpenFoam-1.7.1 (git: 03e7e056c215). There is a tight dependence between "T gas max" and the CFL number in the reactingFoam tutorial case. Lower Courant-numbers lead to lower maximum temperatures and vice versa.

In "applications/solvers/combustion/reactingFoam/chemistry.H" the line

// Chalmers PaSR model
kappa = (runTime.deltaT() + tc)/(runTime.deltaT() + tc + tk);

with an _absolute_ runTime.deltaT() clearly is an error, isn't it?

Also to test mesh dependence i tried this:

I refined the original mesh from the tutorial from 4000 -> 400000 cells (x10 in both directions) and ran the tutorial again. It crashes both in single and parallel at around 0.0007s. I also tried removing runTime.deltaT() from the kappa-equation in the source code, recompiled it, and ran it to the same effect. At some point epsilon becomes negative and the solver crashes.

Any ideas?


Cheers,
Andras

Last edited by andras; July 5, 2011 at 09:15.
andras is offline   Reply With Quote

Reply

Tags
cfl-number, reactingfoam, temperature


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
unable to install openfoam 1.7 using apt-get maazhmd OpenFOAM Installation 7 July 24, 2011 12:18
[snappyHexMesh] snappyHexMesh won't work - zeros everywhere! sc298 OpenFOAM Meshing & Mesh Conversion 2 March 27, 2011 22:11
what is CFL number? cfdiscool FLUENT 3 February 11, 2010 03:56
[snappyHexMesh] external flow with snappyHexMesh chelvistero OpenFOAM Meshing & Mesh Conversion 11 January 15, 2010 20:43
CFL number and time accuracy for LES Li Yang Main CFD Forum 2 August 1, 2002 07:11


All times are GMT -4. The time now is 00:15.