Development of a Low mach PISO solver
 

Hi Foamers

I am trying to develop a low mach number subsonic solver based on original PISO. Since PISO claimed to solve upto mach number as low as 0.001, therefore I have started with the sonicFoam solver and changed the solver to solve PISO for subsonic flow.
Changes are:

1. The energy equation is coupled with the pressure equation to solve it iteratively. (as mentioned in the original PISO)
2. The pressure equation is changed and reference is taken from other subsonic solver. (like XiFoam, as suggested by Henery Weller)
3. solution of continuity equation at the start of iteration is abandoned to preserve the pressure fluctuation at low mach number which would die otherwise.

the source file is attached herewith. see the attachment below.

I have tested this solver with plane channel flow and result are good. I have checked it with forward step problem also.
Let me know if this solver is corrected changed? or if there is any improvement you can suggest then Please make some comment on it.

with regards,

Nishant