Refinement criteria
 

How do I choose the refinement criteria and the value of per cent of cells being refined?

Re: Refinement criteria
 

experience.

Are you refining because you have a converged solution and you want better resolution, or it is not converged?

allan

Re: Refinement criteria
 

I need to perform a grid-independence check.

Re: Refinement criteria
 

well!

double the number of cells in each direction then

allan

Re: Refinement criteria
 

... but even a converged and grid independend solution might be completely wrong.

You should look for the correct solution :)

Re: Refinement criteria
 

search for Richardson extrapolation. It is quite old stuff (around 1920, I guess) but it is a mathematical procedure to obtain a grid independent solution.

you have to start with a coarse mesh and then refine it twice by facor 2 in each dimension (2x2x2 for 3D case). then you to put the results (pressure drop, temperature increase/decrease or whatever into an equation and you will get the so called grid-independent solution. but keep in mind: this does not mean, you get the 'right' solution!

thomas

Re: Refinement criteria
 

This is a respond to Joern and Thomas. If you have a grid-independend solution, you will THE solution for the problem that you have specified.

Re: Refinement criteria
 

You probably have the solution for the mathematical problem you have specified but not for the psysical problem which you want to solve.

Re: Refinement criteria
 

Yes, I agree with you. But this was not the question in the first place...

Re: Refinement criteria
 

BONJOUR il faut rafiner le maillage au niveau des parois et dans les zones de grandes perturbation "zones de recirculation et à l'entrée.