Invalid cell aspect ratio

Dani · Guest

Hi,
I have tried the beta version for a CFD calculation, but I get an error that I can't arrange.
When I start the calculation, it appears the CFD Grid Statistics window with a Fail during the checking. The error, a bit above says: Invalid cell aspect ratio. How can arrange this?

Thanks a lot

Steve Potter · Posts: 296 Location: newcastle

This error means that the CFD grid has lines that are very close together causing the creation of very thin cells which can lead to a very unstable solution. In most cases, you can prevent this from happening by allowing the software to merge lines that are very close together, using the 'Grid line merge tolerance' variable which appears on the 'New CFD Analysis' dialogue. To change this variable retrospectively in order to correct the problem, you can use a trial and error approach whereby you can just increase the merge line tolerance until you no longer get the aspect cell ratio error. You can re-generate a grid using an increased merge tolerance by clicking on the 'CFD results manager' tool, delete the existing CFD project and then create a new one - after clicking on the New button, you will be able to increase the merge tolerance to say 0.02 and see if that corrects the problem and if not, increase it to 0.04 and so on.

We will be introducing a mechanism in due course that will automatically identify grid lines that are close together and display the separation distance.

Regards,

Steve

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