Learning Forum

[2627971244]

 

It always seems to be a problem at both ends，I noticed that the point of the block is not in the correct place, how can I change it?

[Rob]

How thick is the film? 

[2627971244]

oh it is 20 µm

[NickFL]

I am not sure exactly what you are trying to accomplish here, but I will say that SpaceClaim, like most CAD software, does not really like those thin dimensions. Under such circumstances I typically create the model 1000x bigger than it needs to be (so mm become m and µm become mm). After bringing into Fluent, I then simply scale the model down to the appropriate size. (I won't lie, sometimes I forget to scale and the results are utter ridiculous. Doh!)

[2627971244]

yes maybe you are right bro,i want to do a Hydrostatic bearings,so thin oil film is necessary，The size that is too large does not match the reality lol,maybe i can do it by other methods.

[NickFL]

Yes you would create your mesh in the larger scale, and then scale it in Fluent. This can be done using the Task Page->Scale... (where you check the mesh and stuff) or via the TUI, for example: /mesh/scale 0.001 0.001 0.001 where 0.001 is used to scale it from meters back into mm. 

[2627971244]

I tried it, but it's still the case. The model is still too thin, maybe I should try using Meshing.

[NickFL]

Are you trying to create the mesh in SpaceClaim? If so, yes I would agree you would have much better control in ANSYS Meshing. 

To Rob's point down below, what are the goals of your simulation. Your mesh might end up being very large. Will you have the computing capacity to solve such a problem. What are the quanitites of interest? Can a 2D model be utilized? 

[2627971244]

oh sorry my friend,i missed it,iam useing Meshing now,I want to divide the grid into different regions so that the grids in other areas are not very small，2-D is not ok,I have a small workstation，so i think it is ok.

[Rob]

Another consideration will be mesh count. If you want to resolve the oil film you need to mesh to that scale too: 20microns is towards the lower end of what's sensible and means you're going to have cells at 1-2micron scale. Can you afford that level of refinement? 

[2627971244]

I want to complete this model by partitioning the grid into different regions. If the whole world has such small-scale grids, my computer will not be able to handle it.

[Rob]

Which comes back to what you actually need the film layer for. 

[2627971244]

yes lol,thanks for your reply.