compute courant number for 3D geometry
hi foamers.
i have 2 question about coutant number. in 3D geometry coutanr number calcualte as follows for any cell : ux.deltaT/deltax + uy.deltaT/deltay + uz.deltaT/deltaz does openfoam calculate co number same this formula? i read courantNo.H file and didnt understand about how calculate openfaom co number. next question : in my case courant number very little (in order e16). why? 
Hi Saeid,
OpenFOAM does something very similar to your approach. Code:
00037 scalarField sumPhi If you write it out, you will get exactly what you wrote in your post, with twice the amount of terms. I am not entirely sure about the factor 1/2, but my guess is that it has something to do with the fact that you get twice the amount terms. I hope this helps. 
the code you say for openfoam 2.1 . i use openFOAM ext.16. and i work on incompressible flow. in directory src / finiteVolume / cfdTools / incompressible / CourantNo.H
code : PHP Code:
thanks for replying me. 
I'm not familiar with that version of OpenFOAM, but the implementation is not very different actually. deltaCoeffs() returns 1/[distance between owner cell center and neighbour cell center]. I think you should be able to figure out the rest for yourself.

I'm sorry, I was in a hurry. The implementation in OpenFOAM1.6ext is different. It finds the maximum over all faces and uses it to calculate the Courant number.
So this is what it does:  calculate [face flux magnitude]/([distance from owner cell center to neighbour cell center]*[face area])  take maximum over all faces and multiply the resulting value with deltaT 
hi Meindert
youe explanation was perfect and help me alot. thanks very much. 
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