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Tobiasrpr February 2, 2012 14:50

Pressure based solver question

Regarding the predictor-corrector family of methods (SIMPLE, SIMPLEC etc), can someone tell me the purpose of the velocity predictor step? Are there any methods which are based on only pressure correction, without velocity prediction? Any pointer to relevant literature will be much appreciated.


leflix February 2, 2012 17:52

Hi Tobias,

Start to have a look to this here

then read the book of patankar
"numerical heat transfer and heat flow"

and follow with
"Computational fluid dynamics" from Ferziger-Peric

You will find your answers.

For incompressible flows velocity and pressure are deeply coupled. You can not correct one without correcting the other.

FMDenaro February 3, 2012 13:05

As said, pressure in incompressible flows is not a thermodinamic variable and you have no equations governing it (it is a Lagrangian multiplier)... as well, scalar pressure is not a variable to be solved, you need to solve for a gradient of a suitable scalar function that ensures the divergence-free constraint. Solving for the "pressure" equation is therefore equivalent to solve the continuity equation. The relation between such a gradient and the real pressure gradient depends on the method.

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