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Designing a 3D model and applying boundary conditions

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Hi,
I am doing 3D simulation for fluid flow through the stomach and am planning to create a geometry like a cylindrical shell(oesophageus) which merges into a hemispherical shell(stomach) . First of all I am having a lots of difficulties getting the exact geometry(since there is no direct way to create a hemisphere) and secondly when I run the fluid structure interaction module, the fluid portion(which I am assuming to be in the hollow part of the geometry) is not indicated by the software.

I have to solve for the fluid structure interaction in 3D flow with pressure boundary conditions at the top and at the bottom surface.

Any help would be much appreciated.


1 Reply Last Post Apr 18, 2011, 2:51 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Apr 18, 2011, 2:51 p.m. EDT
Hi

of you define "shells" (3D boundary) its OK for the "structural" part, but then you need a solid/volume/=Domain for your fluid part.

To make a "stomach* shape you could use a cylinder and a sphere, that you sweep the sphere over a 1/4 circle to generate a solid volume. You then group everything and use the boundary for the shell and the Domain for the fluid

You still have the issue of the surrounding tissues, that gives some resistance to the fluid pressure, it's not only the thin membrane of the stomach that contains all forces/pressure in such a model
--
Good luck
Ivar
Hi of you define "shells" (3D boundary) its OK for the "structural" part, but then you need a solid/volume/=Domain for your fluid part. To make a "stomach* shape you could use a cylinder and a sphere, that you sweep the sphere over a 1/4 circle to generate a solid volume. You then group everything and use the boundary for the shell and the Domain for the fluid You still have the issue of the surrounding tissues, that gives some resistance to the fluid pressure, it's not only the thin membrane of the stomach that contains all forces/pressure in such a model -- Good luck Ivar

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