exists minimum grid size for Ansys calculation?

sooh2121 · February 23, 2012, 03:34

Hi dear.

I'm CFX user using LES which is turbulent model..

first attempt, minimum grid size is 1e-6 in used domain.

calculation is complated.

but......because of the problem of the y+ value...

I adjusted minumum grid size = 4e-7

and then contect error. floating point overflow..

possible minumum grid size for CFX solver...exists?

Sorry. please understand my English skills..

I look forward to your reponse.!!!!!

lindner · March 7, 2012, 06:39

I don't know if it has something to do with it, but, are you using Double Precision on the solver?

murx · March 7, 2012, 10:34

I don't think there is a minimum size for the elements or CVs. At least not in the range of 4e-7.

However, reducing the element size from 1e-6 to 4e-7 increases the number of nodes in a 3D grid approx. by a factor of 16. So if your original grid was already relatively large, maybe this could be a reason for the problem.

February 23, 2012, 03:34	exists minimum grid size for Ansys calculation?	#1
sooh2121 New Member Ahn Join Date: Feb 2012 Posts: 1 Rep Power: 0	Hi dear. I'm CFX user using LES which is turbulent model.. first attempt, minimum grid size is 1e-6 in used domain. calculation is complated. but......because of the problem of the y+ value... I adjusted minumum grid size = 4e-7 and then contect error. floating point overflow.. possible minumum grid size for CFX solver...exists? Sorry. please understand my English skills.. I look forward to your reponse.!!!!!

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March 7, 2012, 06:39		#2
lindner Member Join Date: Mar 2010 Posts: 42 Rep Power: 5	I don't know if it has something to do with it, but, are you using Double Precision on the solver?

March 7, 2012, 10:34		#3
murx Member Max Join Date: May 2011 Location: old europe Posts: 61 Rep Power: 3	I don't think there is a minimum size for the elements or CVs. At least not in the range of 4e-7. However, reducing the element size from 1e-6 to 4e-7 increases the number of nodes in a 3D grid approx. by a factor of 16. So if your original grid was already relatively large, maybe this could be a reason for the problem.