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Help with optimizing my mesh

35 Views, 5 Replies
02/06/2018 12:39 PM

Hello, I am trying to simulate a pipe where the diameter gradually increases, then returns to normal, like a bulb. When meshing, I initially autosized, then moved the size adjustment slider to 0.4, then surface and gap refined (with 8 fluid gap elements) and created a wall layer (7 layers, layer factor = 0.25, layer gradation = auto). I then performed a mesh adaptation with 4 cycles. I am happy with the quality of the mesh, but my simulation is taking much too long, is there a chance someone could look at my mesh and give me some pointers on how to speed up my simulation without losing much accuracy?

 

Thanks a lot,

Joe

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Message 1 of 5 ( Views: 35 )

Re: Help with optimizing my mesh

02/06/2018 1:36 PM

Hi @joseph.landes,

 

Thanks for reaching out to us on the forums. It sounds like you took a fairly good approach here. It's hard to say when you mesh is going to start affecting your results. For starters, you could try leveraging the "Allow Coarsening" button in Mesh Adaptation. This will coarsen the mesh in areas which are over meshed and not critical. If not selected, mesh adaptation will only tighten the mesh. 

 

Generally speaking, I think it is a little more efficient to start with a coarser mesh and then tighten it until you results stop changing. Your approach to getting your initial mesh (autosize, adjust to 0.4, surface gap refinement, etc) probably set up a great first mesh. I would have run with that, not using adaptation, and then recorded your results. Personally next I would clone the scenario, enhance the mesh by selecting the volumes and moving the slider bar to 0.7, and then rerun and record results. This is basically a manual mesh sensitivity study.

 

Any combination of manual mesh study/ mesh adaptation will work, but the above approach lessens the chance of over meshing right from the get go.

 

Thanks, 



Matt Bemis

Technical Support Specialist


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Message 2 of 5 ( Views: 27 )

Re: Help with optimizing my mesh

02/06/2018 1:51 PM

Hi @matt.bemis,

 

Thanks a lot, thats really useful advice! Also good to know that I'm on the right tracks as far as meshing goes.

 

Kind regards,

Joe


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Message 3 of 5 ( Views: 20 )

Re: Help with optimizing my mesh

02/06/2018 3:12 PM

Hi @matt.bemis,

 

I tried increasing th emesh by 0.7, but the number of elements went from ~2M to ~10M. Do you possibly have any other suggestions?

 

Thanks,

 

Joe

 


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Message 4 of 5 ( Views: 17 )

Re: Help with optimizing my mesh

02/06/2018 3:13 PM

Hi @matt.bemis,

 

I tried increasing th emesh by 0.7, but the number of elements went from ~2 M to ~10 M. Do you possibly have any other suggestions?

 

Thanks,

 

Joe

 


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