Milne Ando
Subscriber

Hello sir,

yes I've added report of mass flow rate to monitor the result. I'm still trying to find the optimal settings that are much stable and robust; however, the recommened values for factors seem not necessarily lead to good result. As the pic shows, residuals surged too quickly, even though my time step size was quite small. I used PISO scheme with PRESTO!, and under-relaxation factors of 0.5 for both pressure and momentum. The user guide says,

"When you use PISO neighbor correction, under-relaxation factors of 1.0 or near 1.0 are recommended for all equations."

hmm but I think 0.5 is aggressive enough. What should I do to overcome this... hope you can give any suggestion, thank you so much.