### Re: salomeToElmer - export Salome mesh to Elmer

Posted:

**02 Dec 2019, 21:17**Yes, I get that too. Does it mean that if I call each boundary/body with these names in the sif file it will normally work?

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Posted: **02 Dec 2019, 21:17**

Yes, I get that too. Does it mean that if I call each boundary/body with these names in the sif file it will normally work?

Posted: **03 Dec 2019, 02:47**

That i have never tried or tested.

Posted: **03 Dec 2019, 14:04**

Do you know what happens if we don't assign a BC in a boundary? I've read somewhere that it behaves as hard wall (with Wave Flux 1 = 0), is that true?

Posted: **03 Dec 2019, 22:36**

I believe it varies for every solver or ElmerModel in the model manual. I think in general if nothing is assigned to a boundary, then nothing happens or is transferred through (either into or out of the mesh) at that boundary. This will have different effect in every solver. For example in a heat transfer analyses no heat transfer across the boundary is equivalent to symmetric boundary condition. In solid mechanics no definition at a boundary means it is free to move/defect.

Posted: **04 Dec 2019, 11:44**

Hi,

In FEM the "do nothing" BC or the "natural" BC depends indeed on the equation. When a weak form of the PDE is written a boundary integral term appears (Neumann BC). If this is not modeled it is zero. The boundary integral is typically some kind of flux (heat flux, electric current, normal force, etc.).

-Peter

In FEM the "do nothing" BC or the "natural" BC depends indeed on the equation. When a weak form of the PDE is written a boundary integral term appears (Neumann BC). If this is not modeled it is zero. The boundary integral is typically some kind of flux (heat flux, electric current, normal force, etc.).

-Peter