[funkvps]

Recently, I've faced a very strange convergence problem in fluent. I'm trying to get a concept understanding the fluid condition inside a cycle distributor.

So the following geometry and mesh was created. mesh quality is good due to simple structure.



when I'm modeling flow inside from location A and outside from location B1~B18. I set location A to mass flow inlet, location B1~B18 to pressure outlet, the calculation can quickly converge to a solution, and result is reasonable.

However when I'm trying to model the reverse direction flow, which means the flow goes in from location B1~ B18, goes out from location A. the convergence is really odd.

this time, I set location B1~B18 to pressure inlet or mass flow inlet or velocity inlet, location A to pressure outlet, the calculation never converge, but give results like below (The second picture shows the residual plot). After checking regarding the monitoring point/surface pressure, flow, it's also keeping oscillating.

Any one knows why this happens? is the number of inlets to much?

Really thanks

[LuckyTran]

That's definitely a converged solution. Why do you say it's not converged? You probably need to recalibrate your understanding of convergence.

[funkvps]

Originally Posted by LuckyTran

That's definitely a converged solution. Why do you say it's not converged? You probably need to recalibrate your understanding of convergence.

Sorry for my mis typing, the second picture shows the residual vs time, as indicated, the residual keeps high all the time. When I check the check point/surface pressure/flow, it's also oscillating.