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[dodonn4]

Hi everyone,

I am working on a fluent simulation to model natural convection heating inside a bag of liquid. I was able to successfully simulate it and get accurate results, then I changed the geometry slightly. The changes to the geometry were not significant at all, the general size and shape are still the same. It is relatively simple geometry too; just an elliptical cylinder that tapers inwards towards the top.

However, now I noticed that my results significantly vary with different mesh sizes. For example, if I have 150k+ elements in my mesh my results are around 20-30% different than when I have 100-130k elements. And if I have over 250k elements in my mesh the simulation fails.

Why does the mesh have such a significant impact on the results?

[Keyur Kanade]

For student license the cell count limit is 512K.
The results would be more accurate when you capture geometry and flow with refined mesh. You may need to do mesh independent study for that. There must be some posts on forum about this.
In general coarse mesh and refined mesh will have different results as they capture geometry and flow differently.
Please check your geometry changes. If may be small but it may be impacting flow at that position.
Regards Keyur
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