Learning Forum

[Bergheden]

Hello.

I have made a CFD model in 3D, to simulate airflow in large industriel buildings. This has first been done in 2D without any problems, but when switching to 3D i encounter a problem. The contour plots seems to have "cracks" which results in the XY-plot for velocity being incomplete. This happens no matter how fine or course the grid is.  Have any of you experienced this, and if so found a solution?

The turbulence model used is k-epsilon with "standard wall treatment".
Methods used is SIMPLE.

 

[Amine Ben Hadj Ali]

Double check graphics and driver. If all run a single iteration with zero as number of cpus

[Bergheden]

Double check graphics and driver. If all run a single iteration with zero as number of cpus

Hello Amine.

I have tried what you suggested and it seems to work, but is there a long term solution? With only one iteration, the model is far from converged, and without parallel processing, the total processing time is extremely long.

Best regards,

Oliver

[Rob]

The cracks are probably related to the parallel partitions and can usually be ignored: they just affect the images. 

Not seen that issue with a line graph, how does it look if you plot against position (x, y or z)? 

[Amine Ben Hadj Ali]

And make a screenshot of the contour panel.

[Bergheden]

Update:
The problem seems to be with the parallel partitions as rwoolhou mentions. I have now tried simulating with serial, and that seems to solve the problem completely, both the cracks in the contour plot and the issues with the line graph. This has been tested with multiple models and seems like a consistent solution. Thanks for the input both rwoolhou, and Amine

- Oliver

 

[Amine Ben Hadj Ali]

Nice
But does it still happen in parallel?

[Bergheden]

Yes, i does. I've tried in multiple CFD-models, and even with different versions of ansys (19.1, and 2019 R2). This seems to be consistent, at least for my case in 3D. No problems with serial so far.

- Oliver 

[Amine Ben Hadj Ali]

Then please as I asked before: make a screenshot of the contour panel. I want to see the settings there.

[Bergheden]

I this what you are asking for?

- Oliver

[Amine Ben Hadj Ali]

Ok that is the issue: better to create a new surface zone (search for it in Fluent new search feature. Probably under domains if you follow the ribbon) for the domain and color that.