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turb April 18, 2006 17:13

PISO for high Courant Numbers
1) Can PISO be used in transient simulations with a high Courant Numbers (say, >20)?

2) Can it be stable (with a lot of inner iterations -> is that all I need)?

3) is it more stable than SIMPLE for these cases (transient, but with a high Courant)?

4) good references?

Thanks a lot.

newposter April 20, 2006 11:42

Re: PISO for high Courant Numbers

The original version of PISO was developed for transient calculation with small timesteps, so you have also small Courant numbers (<1) in this non-iterative variant. If you are running PISO like SIMPLE with outer Iterations you do not need small Courant numbers, but the convergence rate of PISO will then not be better or faster than SIMPLE! See also the paper "Solution of the implicitly discretised fluid flow euqations by operator splitting" by R.I. Issa!

Good Luck!

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