# Courant criteria

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 August 8, 2016, 08:04 Courant criteria #1 New Member   Samraj Manickam Palvannan Join Date: Jul 2016 Posts: 25 Rep Power: 3 Sponsored Links Hello all, I have been trying a flow simulation. I get missing elements error which i suppose, is beacuse of Courant criterion. I calculated Courant number from division of time step to grid size. I get unrealistic cfl number from that. Could someone please help me with that? thank you very much. user01 likes this.

September 7, 2016, 06:38
#2
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Reynolds
Join Date: Apr 2016
Location: Spain
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Quote:
 Originally Posted by samraj Hello all, I have been trying a flow simulation. I get missing elements error which i suppose, is beacuse of Courant criterion. I calculated Courant number from division of time step to grid size. I get unrealistic cfl number from that. Could someone please help me with that? thank you very much.
Hi,

Which is the velocity of the node in the point that you get unrealistic cfl number? And you time step?

Regards.
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 October 7, 2016, 11:32 #3 Member   Adwaith Gupta Join Date: Dec 2015 Location: USA Posts: 45 Blog Entries: 1 Rep Power: 3 Courant number is velocity in cell times time step divided by the cell size. You are missing the velocity component in your calculation.

November 3, 2016, 03:14
CFL number
#4
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Kenneth
Join Date: Oct 2016
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Quote:
 Originally Posted by thunde47 Courant number is velocity in cell times time step divided by the cell size. You are missing the velocity component in your calculation.
Hi sorry I am new to CFD, i do not understand the velocity in cell ? Do I define this or I get it from the mesh information ??

Thanks!

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