Hello Everyone,
@varunsura , @PhilippB94, @durgesh786 , @agupta , @fhnx ,@LoganZundel , @slibbi , @kianz89
IMPORTANT NOTE: for all who are facing issue of strange simulation results e.g the figure below
What was causing this ?
The reason for this was a lot of illegal cells ( bad quality ) in the mesh. You can check that by clicking the meshing log as shown in the figure below:
In most cases, the number was around approx 200 illegal cells which then requires more iterations ( about 6,000 as already mentioned by some users) to reach the correct result. Or for some it may cause the simulations to crash.
(This can happen in some cases, when we do too many iterations in a specific step of the meshing algorithm for meshes of moderate size.)
If that is the case for you, then please read the Fix below.
How to Fix this ?
To avoid too many illegal cells, we can reduce the number of iterations for:
nFeatureSnapIter to value “1” under Snap Controls as shown in the figure. (If the mesh is of moderate size, as in this case, then a value <= 3 is sufficient)
This has also been UPDATED in the 2nd figure in the meshing part of the tutorial
.
- So , please making the above change, click Save and Start again the meshing job.
(this time it would also finish quicker than before)
By doing so, the number of illegal cells should be reduced to less than 50 which is fine for the solver. Then the simulation would converge to the correct result in 1500 iterations/time and should show a convergence plot similar to below:
NOTE: If you have already done a simulation with the current mesh for 6,000 iterations and have the correct results, then that is also fine and your homework is accepted.
This should solve the issue, and if you face further problems please let me know by tagging me.
Best,
Ali Arafat
CFD Simulations Engineer