Dear Sir:

Here are some sources would fit your problem,

Also, ANSYS  FLUENT  tutorial in the chapter of 'solvers'  has some information about simulation in PISO under different circumstances. 

Dear Amir,

As you want to simulate a process I think, the problem will be unsteady and in the case of transient or unsteady simulations PISO sounds to be more effective in comparison with SIMPLE or SIMPLEC. 

thank you very much. The SOLA algorithm is non-iterative and has the benefits of cpu time reduction. Could you introduce me a good source for studying PISO?

Best Wishes

The following literature may be useful for your research

Free surface flow and application to filling and solidification of liquid metals

Abstract: A three dimensional control volume, free surface technique of Scalar Equation Algorithm has been developed as an attachment to PHOENICS and  Harwell Flow 3D CFD codes.The filling model without heat transfer and solidication has been validated against experimental data in both water experiments and actual mould  filling experiments.It has been compared  against predictions from SOLA- VOF and MAC methods.      

gala.gre.ac.uk/6128/1/(Andrew)_Koon_Sang_Chan_1994.pdf

Here are some sources would fit your problem,

Also, ANSYS  FLUENT  tutorial in the chapter of 'solvers'  has some information about simulation in PISO under different circumstances. 

 Goodluck

There is not the best, because that depends of  the problem:

 a) SIMPLE algorithm is used more for steady-state problem

http://www.cfd-online.com/Wiki/SIMPLE_algorithm

b) PISO algorithm is more for unsteady analysis, depend of  your investigations, that is the case of unsteady partial cavitation problems.

http://openfoamwiki.net/index.php/PISO

In openFOAM there is PIMPLE, which is PISO and SIMPLE together. PIMPLE calls the algorithm depend of problem conditions.

Maddali's Ref. is very useful. I have used both SIMPLE and PISO and found little difference. Therefore the Simpler the Better!

Numerical simulation related to casting needs several algorithms and modeling techniques as follows:

1) PISO :coupling flow field to pressure in case of unsteady problem

2) SOLA-VOF will be required to solve free surface(this is fixed grid method; there are some alternatives for solving free surface depending on accuracy and time consumption)

3) enthalpy method to solve phase change phenomena

4) numerical models for solving magnetic field coupled with flow field

Good Luck~!

Dear Amir Baghani

SIMPLE or SIMPLEC are not good for unsteady analysis so you have to select PISO algorithm to couple the flow field characters of velocity and pressure depend on your investigations.

Dear Sir:

Here are some sources would fit your problem,

Also, ANSYS  FLUENT  tutorial in the chapter of 'solvers'  has some information about simulation in PISO under different circumstances.