Hi,
This is the sign that your solution is diverging. You can ignore the message if the number of cells where it crosses the limit is just a very small fraction of your total number of cells. If the cell count is significant, you can try doing this
1) Refine mesh where you expect sharp velocity gradients
2) Reduce the relaxation factors
3) Reduce the time step size and increase number of iterations per time step if you are running a transient case.
4) Also check the applicability of the turbulence model you are using for your problem.
Hi,
that message is often when you use to high Courant noumber or order of equations at begining. Try to increase "stability" of your solution by many iterations at lower parameters and then increase the parameters.
Hi,
This is the sign that your solution is diverging. You can ignore the message if the number of cells where it crosses the limit is just a very small fraction of your total number of cells. If the cell count is significant, you can try doing this
1) Refine mesh where you expect sharp velocity gradients
2) Reduce the relaxation factors
3) Reduce the time step size and increase number of iterations per time step if you are running a transient case.
4) Also check the applicability of the turbulence model you are using for your problem.
You can try reducing the Co number alias the time step or initializing the solution with the results of a steady calculation.
F.
Hi Sepideh,
In the initialization panel, reduce the default values of k and e from 1 to 0.001.
Best,
Siamak Agahzamin Franco Concli @ Merda Tomasz :thanks for your answers
In my opinion, keeping above suggestions in mind, you should consider boundary conditions too. Because of setting reasonable boundary conditions other parameters will behave in range accordingly.
Regards
Check your mesh (especially near corners or edges) or boundary conditions (at outlet). Above message is created by ANSYS when the ratio of turbulent viscosity and the laminar viscosity exceeds 1e5. Is there any outlet in your geometry?? probabaly thats where this backflow is happening. let the simulation run and it should disappear after some iterations.
if not u can reduce URF or u can goto soluiton control/ limits/ max tub vis and add few zeros but All this is not recommended and will effect your results.
@Hardik mistry and all,
I have tried all options but still stuck with this error. Is this an error, as my solution is getting converged but the "turbulent viscosity limited to ... " is for around 50% of total cell count
I got stuck during a ansys fluent simulation for a PCM based heat sink.
Kindly help me out
Did you work on high order equations? Sometimes it is better to start at first order equation and when calculations were stabilized then use higher order. Not every order of equation can give the solution. Also check quality of mesh and size of the element.
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