Thank you for your information. I was under this impression, but can't
seem to get gmsh to actually mesh the volume inside the "tunnel" and
outside the shape. Rhino can only model surfaces I believe, not
solids. Would this be the problem? I am sending a step file into gmsh
that contains the surface of the tunnel and the surface of the shape
inside, both show up as volumes when I check the statistics. I am
wondering about the "merge" command, could this help? I am not sure
exactly what it is doing, but could I extrude a solid inside gmsh and
merge with my non-solid surface? Is there something in Rhino I can do
to help? Thankyou - Bob
César A. Vecchio Toloy wrote:
Bob, I think you're making a common mistake among CFD newcomers: you're
modelling the bodies but not the air. I mean, the solid of your STEP must be
the air and not the bodies surrounding it or the bodies in it. I give you the
following example:
Let's suppose you want to model the flow around a sphere. First we make a solid box which
delimits the space we will model (even if you are modeling something in free space, you
must limit it in the model). Now, to represent the sphere you must "take it
out" from the solid box, for example by boolean substracting a solid sphere from the
solid box, so you will end up with a solid box having an spherical cavity. That is the
correct way of modeling in CFD with these kind of general purpose meshers.
If you already knew this, I apologize. Check the message console in Gmsh (under
"tools" menu) to see if there was some error. Perhaps you could be having extra
surfaces or lines, that happened to me with some Rhino versions. If the STEP file is not
very big, you can try attaching it.
César
On Mon, 01 Nov 2010 15:13:55 -0600
Bob Basham <[email protected]> wrote:
Hi All,
I am pretty new to CFD in general. Just starting to figure out
gmsh in order to run some simulations using ELMER. I need to put a 3d
shape inside of a wind tunnel. I have created the shape in Rhino 3d
and finally have success with importing to gmsh as a STEP file (IGES
gave all sorts of little holes in surface). I have tried and tried to
get a 3d mesh of the volume inside the "tunnel" and outside the shape,
no luck. I am sure that I am missing something basic. Can someone
point me in the right direction. I have lastly tried merging a STP of
the "tunnel" with a STP of the surface, but can't get a 3d mesh of the
inside. I get a self intersecting error. I have successfully used a
half model (like symmetry), the surface and tunnel are joined at the
middle. I would like to have my surface suspended in the tunnel
though. Thank you very much!
--
Bob Basham
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Bob Basham
White Cloud Aviation LLC
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