[Roger9318]

Hi everyone !!!



According with the literature, the algorithm PISO is one of the most suitable algorithm for transient analysis. I found many publications related with this topic. these publications helped me a lot (really really helped me). However I'm still working on that. The PISO algorithm has been already developed in an in-house FORTRAN code based on the finite volume technique. However the program diverge also I have doubts and that´s the reason for this post. Hopefully you can (in some way) help me.



Which are the main difference between the iterative PISO and noniterative PISO? I have an idea and I represented in the attached flow charts images.


flow chart iterative piso.jpg

NONiterative.jpg


Another of my concerns is related with the following term, which appears in the source term of the second pressure correction equation and in the correction of velocities. Is it correct how I represented?

relacion.jpg


The PISO algorithm is implemented in a forzed convection(channel) problem. After that, I’m going to develop in a problem with natural convection but before do that the PISO algorithm needs to be done


How did you do to reach the convergence?

Accordig with your experience which are the better parameters (Δt-step time, under relaxation factors, solver -LbL-x,lbl-y lbl adi, etc..) to reach the convergence? I know it depends on the problem but which were the best for you?


Thank you in advanced

Best regards,