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Old   July 3, 2009, 09:33
Default convergence of the solution
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amar
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Dear all

I'd like to know what is the criteria to be sure that my solution is really converged.

thanks a lot
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Old   July 3, 2009, 09:45
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If you have a goal, then monitor it (force, pressure at inlet , massflow rate, etc..).
You achieve convergence if the monitoring doesn't fluctuate anymore with iterations
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Old   July 5, 2009, 10:08
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Convergence criteria are very problem dependent. My usual approach is to monitor a variety of variables (e.g. velocity at several points, forces on the body, mass flow rates) - the more the better really. As -mAx- says, once the values of these have stabilised then you have a converged solution. BUT only IF your residuals have fallen by a suitable amount from their initial values (don't rely on Fluent's default 10e-3 convergence criteria). What is a suitable amount? Again, very problem dependent, but for a steady-state external aerodynamics type problem I would expect the continuity residual to drop below 10e-6 and the velocity (momentum) residuals to drop much lower than that. The Fluent user guide has some helpful guidance on this too.
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