Trouble Choosing Inlet Boundary Face

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Tony Renaldo

Mar 3, 2020, 4:49:59 PM3/3/20
to CRIMSON Users

I'm trying to go through parts of the workflow presented in the Tutorials (with some modifications) with my own geometry. I'm having trouble assigning a boundary condition at the proper inlet. It currently is reading that my inlet face is a "wall", instead . I believe I asked about this in the past and it turned out to work regardless of the Type of Face. However now it's not letting me choose it for my boundary condition. 

Are you able to suggest how I can alter the type or if there is something else I need to do to have the geometry be registered correctly? I have attached the file for reference.

All the best,

Arthurs, Christopher

Mar 4, 2020, 7:03:54 AM3/4/20
to Tony Renaldo, CRIMSON Users
Hi Tony,

I took a look at your model, and I was able to run.

The labels "inflow" or "outflow" don't really mean anything, but "wall" does. However, they are still just labels, as opposed to anything computational - so it's quite straightforward to work around this.

Incidentally, the "wall" label appears to be due to some quirk of the geometric model you imported. Could you share that file, so we can log it on our bug tracker as something we can improve on, please?

As to the work around, what I did was:
1) I used zero-pressure BCs on all outflows (the type here is not critical; this was just a test). I was able to select faces whether or not they were tagged as "wall" by clicking the button with the circle on it in the image below and enabling "allow any faces to be selected". This is possible for any BC type - the image shows it for the no slip BC

2) When applying the no slip boundary condition, instead of selecting "apply to all walls" (which uses the "wall" tag), I manually selected the external surface of the model.

It ran fine at timestep 0.001s for 2000 steps.

One thing I will say is that - as I'm sure you're aware - your mesh is far too coarse. The renals, in particular, are not resolved geometrically, and so certainly not numerically.

Best wishes,


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Chris Arthurs, D. Phil.
King's Prize Research Fellow
Imaging Sciences and Biomedical Engineering
King's College London
CRIMSON Cardiovascular Modelling Environment:
Twitter: @carthu15p
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