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initial residuals in icoFoam

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Old   December 12, 2014, 09:55
Default initial residuals in icoFoam
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Mehrez
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Hi,
My question is about the icoFoam solver (used for transient incompressible Newtonian fluids). Does someone know how the initial residual is evaluated ? I mean the equation.
Thank you in advance.
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Old   December 13, 2014, 03:29
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Tushar Chourushi
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Have a look at the following post, where you will find that L1 norm is used.

Residual definition of OpenFoam

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Best Regards!
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Old   December 14, 2014, 14:24
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Quote:
Originally Posted by Tushar@cfd View Post
Have a look at the following post, where you will find that L1 norm is used.

Residual definition of OpenFoam

-
Best Regards!
Hi,
Thank you for this answer.
It is mentioned on the OpenFoam doc that "the residual is evaluated by substituting the current solution into the equation and taking the magnitude of the difference between the left and right hand sides".
So if I understand well, from the PCG.C file where
solverPerf.initialResidual() = gSumMag(rA)/normFactor
The (rA) is the difference between the left and right hand sides of the equation to solve ?
If we consider the IcoFoam solver. At which step of the PISO algorithm the residual is computed ?
You can see here the numbered equations :
https://www.dropbox.com/s/m848engmee4qawy/Algo.pdf?dl=0
Can you please based on the this file tell me the complete formula of the residual ?

Thanks in advance !

Mhrz
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