[kurubin]

Dear All,

I am pretty new to this forum and therefore I would like to say HI to all of you .

I am facing a problem, whereby, I imported an .STL file of an aorta in DesignModeler, and I linked this geometry to ANSYS mesher. Now, when I open the Mesher, what I get is something similar to the following image:



and zooming in:



My first problem is when it comes to name select the boundaries i.e. the inlets, outlets and the wall. I know that the Virtual Topology tool exists which may be a bit of help but I did not manage to work with it either. Do you know a way how to transform the wall into one whole surface rather then it being made up of a lot of triangular faces? (and even the inlet and outlets)

Moreover, is a surface body meshable? Is it considered a solid body? Could it be that this 'surface body' is causing me the problems?

Regards,
Kurubin

[scipy]

You need to actually prepare the geometry for a CFD simulation. Import this model into DesignModeler or SpaceClaim and play around with creating Enclosures or some other ways of creating an actual fluid volume. From the orientation of your model I can't really see which two surfaces form the body (is it symmetric or not), does it form a water-tight volume. If it does, you can use a sewing operation to try and form a solid (which you can change to a fluid type later on).

[kurubin]

First of all, thank you for your kind reply!

The three branches at top are three outlets and the there is the inlet visible in the first diagram and there is also another outlet which is not visible here. The second diagram is just a zoomed in diagram so that I could explain better the type of surface that I am getting.

I once saw a tutorial of a similar case, whereby the surface of the artery is not made up of these many triangular faces as I do, however I do not know how it is done and that is my problem :/ . The link to this tutorial is the following so that you could understand me better:

https://confluence.cornell.edu/displ...+Artery+-+Mesh

Regards,
Kurubin

[scipy]

OK. The problem is that the Cornell tutorial deals with a clean and water-tight geometry in a STEP file that already has a "body" inside it, meaning a zone of fluid/solid.

What you have is an .STL file that's a result of a 3D scan most likely. In previous versions you couldn't even import this type of file into DM or work on it in ANSYS Meshing. I don't really know how that situation works now or are there capping faces on your inlets/outlets. If there are, you could try what I suggested - sewing the body together out of these surface bodies to create a solid and then using named selections to create inlets/outlets/walls.

If you can post your .STL file here as an attachment or link to it on Dropbox/Google Drive/similar I can try the same procedure quickly. What you also might want to look into is ICEM CFD. I think there's even a tutorial in the documentation dealing explicitly with a blood vessel that starts from a .STL geometry.

[kurubin]

Actually I tried using the sewing option which I think is the tool I need for my situation, however I encountered another problem whereby I noticed that the .stl file that I imported was imported in a much larger physical size than it actually is, and I think the problem arised from this factor and in fact when I try to use the 'sew' feature, an error message states that the size of the geometry is out of range. Therefore if I manage to import the geometry in its actual size, my problem diminishes a lot. May I kindly ask you whether you know anything about this problem, please?

If you could give me your email address I would share the Google Drive link with you, no problem.

Regarding ICEM CFD - yes I know about the tutorial however I always worked on ANSYS Mesher and Fluent and unfortunately, at the moment I do not have much time to learn a new interface, but thank you as well for the suggestion.

[Gabri12]

Dear kurubin,

I wonder if you still active here, i would like to know if you have managed to solve this problem for meshing name selection. thank you

[scipy]

I think that my recommendation still applies.. Don't even try to deal with STL geometry in ANSYS Meshing. Either move to FLUENT Meshing (TGrid) or ICEM CFD. You're going to have a much easier time. Meshing named selections themselves is rarely a problem if the geometry is not dirty/broken/riddled with holes etc.

[uttam.shubham@gmail.com]

Stuck with .stl file imported from 3d scan file. I need to run cfd simulation but not able to generate mesh. How to do meshing in cfd from imported mesh