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-   -   Significance of COURANT nUMBER (https://www.cfd-online.com/Forums/fluent/45975-significance-courant-number.html)

sridhar September 9, 2007 19:13

Significance of COURANT nUMBER
 
Hi everyone, I am doing supersonic flow study in a combustor.I want to know how important is the effect of Courant number on the solution ,convergence etc. I am presently using Courant number of 0.5. How far can I change it from my present value to get better results.

Regards sridhar


Joe September 10, 2007 13:56

Re: Significance of COURANT nUMBER
 
A CN of less than 1 is always satisfactory for an implicit solver. Practically a RMS CN <= 1 and MAX CN <= 5-10 is usually satisfactory for adaquate accuracy for an implicit solver. You can go bigger but you must then show solution insensitivity to a CN > 1.

sridhar September 12, 2007 12:47

Re: Significance of COURANT nUMBER
 
thanks for the rply .. just help me out with another small doubt of mine ..mine is an injection problem and the main flow is supersonic with sonic injection .I would like to know . should I start with UNSTEADY solution or start with STEDY SOLN and then switch to unsteady solution.. Please suggest ..thanks

Kaiser Matin September 26, 2007 17:14

Re: Significance of COURANT nUMBER
 
Start with a steady solution and then do the unsteady soultion.


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