If my solution is converged ?
 

I want to use the time-dependant solver to get the steady state. And I also monitor some important parameters, such as temperature, vof...
After some iterations, I found these parameters almost do not change, but the residuals remains at a high value(10-2) and goes flat. I wonder if I my problem is converged ?
The residula and monitor look like this >
Attachment 1011Attachment 1012

Residuals becoming flat may indicate:
1. Your solution has converged, or
2. This is the minimum residual possible with your current grid.

For further reduction in residuals, you may have to refine or adapt the grid.

Yeah, I agree with srjp. You're going to need to refine your grid. I would recommend plotting contours of mass imbalance (since your continuity residuals didn't converge) and refining where they are high.

-sean

you both wrong.
this is transient solution and if one decrease the time step the residuals will decrease too.
you execute 1 ineration on 1 time step?

the continuity residuals are too high.
reduce your time step

Sorry, I thought it was steady state simulation.
May be after frustration of seeing so many flat residuals !!!
Agree with mAx on the timestep reduction.

ditto.

-sean

Yes, 1 interation on 1 time step at beginning, because I want save computation time. And then I increase the interations each time step, and the residuals also remain flat.

forget 1 iteration per time step
try the default settings, eg: 20 iterations per time step
I would also recommend you to start your unsteady computation from a well converged steady solution

Character of success iteration???
 

Hello!!!
I'm a new user in FLUENT. I've read your Post. I wanna know what is the indication that we have success iteration??
I've thought that FLAT graph on the Residual graph is the indication!!!
Am I wrong???:rolleyes:

I think when the we get converged solution, the residual will go flat. But at the same time, the residual should fulfill the criterion, such as 10e-4,10e-5...

Flat or not it is no matter. If iteration converged then it is. I think so.

Regards.

Is there an equation to prove it?? just to know how much convergence value!!!

there is navier-stokes equation.
and http://en.wikipedia.org/wiki/Residua...rical_analysis)

regards.