Get To Know Your Mesh.pdf

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• Does the mesh look like the real world/CAD model?

• Are there 4-5 elements through narrow fluid channels? • Are fans, blowers and resistances adequately meshed? • Is the model mesh independent? • This usually takes a few solves to establish

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1. Mesh Controls 2. Solver Controls

If you have CFD open, feel free to grab the files and you can run through a couple of examples as we go: https://autodesk.box.com/cfd21 Autodesk Help Webinar Series

1: Mesh Controls

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This is a bad mesh Is the mesh fine enough, that it accurately represents the CAD model?

This is a better mesh

If the meshed does not compare to the real world model, the mesh is too coarse and requires refinement.

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Poor

Good

The boundary layer is huge compared to the tetrahedral elements

Plenty of elements across the gap and a small boundary layer

Utilise Surface and Gap Refinement When using Gap Refinement, setting 3 Fluid Gap Elements generally seems to be the optimum Think about Thin Solid Elements Tip: 4-5 elements is a nice rule to use Autodesk Help Webinar Series

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dP = 0.397 Bar (The results here were clearly mesh dependent) Autodesk Help Webinar Series

dP = 0.230 Bar

Todd

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2: Solver Controls

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LOW  NAR  

HIGH NAR 

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Slide Deck Available to Download : https://autodesk.box.com/cfd21

Slide Deck Available to Download : https://autodesk.box.com/cfd20