Minimum Mesh Volume and Computational Precison

idrama · June 10, 2010, 04:40

Hey Foamers!

does anybody know how small the mesh can be; when I violate the computational precision?

Cheers

hjasak · June 13, 2010, 08:44

In double precision you have 14 significant digits; for stabilisation around zero we use VSMALL=1E-300 and for stabilisation around 1 we use approx 2E-14.

My guess is that 1e-14 might start causing you trouble since some normalisations may be done badly. This is something you can fix yourself

but it may be a bit tricky...

Above 1E-14 you should be just fine.

Good luck,

Hrv

June 10, 2010, 04:40	Minimum Mesh Volume and Computational Precison	#1
idrama Senior Member Claus Meister Join Date: Aug 2009 Location: Wiesbaden, Germany Posts: 241 Rep Power: 17	Hey Foamers! does anybody know how small the mesh can be; when I violate the computational precision? Cheers

June 13, 2010, 08:44		#2
hjasak Senior Member Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,905 Rep Power: 33	In double precision you have 14 significant digits; for stabilisation around zero we use VSMALL=1E-300 and for stabilisation around 1 we use approx 2E-14. My guess is that 1e-14 might start causing you trouble since some normalisations may be done badly. This is something you can fix yourself but it may be a bit tricky... Above 1E-14 you should be just fine. Good luck, Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

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