Elmer Discussion Forum

Does anyone know of a tutorial for the Advection Diffusion Solver. I have been trying to use it and a wee bit confused.

Gary R

I tried loading the .msh file directly and it works. Wish I had known this a long time ago. This saves the whole ElmerGrid step and a lot of files.
Thanks
Gary R

Hi all, Operating System: Debian GNU/Linux 11. KDE Plasma Version: 5.20.5 KDE Frameworks Version: 5.78.0 Qt Version: 5.15.2 Kernel Version: 5.10.0-13-amd64 OS Type: 64-bit Processors: 4 × AMD FX(tm)-4350 Quad-Core Processor Memory: 15.6 GiB of RAM Graphics Processor: AMD CAICOS Elmer version 9.0 Gms...

I found the problem. When I ran validation on the Freecad sketch I found 3 missing coincidences. When I fixed these, the problem went away. The moral to this story is run validation on your sketches before proceeding.
Gary R.

Thanks Kevin
If anyone can shed light on why the notch happened it would be both appreciated and instructive.
I now have a problem with ElmerGUI (I don't think related) but will post that on the ElmerGUI forum.

Thanks again
Gary R.

I created a simple pipe for a diffusion test. The pipe is in two sections. It was created with FreeCAD and exported via a .brep file to gmsh. PipeMesh.png , The result, as shown, has a large notch in the mesh. Multiple attempts have failed to improve things. How can I fix this? The .brep file is att...

Thanks for the reply. I have read the models manual several times but your reference didn't register. After rereading that part, I concluded that I am using the wrong formula. My model seems to lend itself to the use of the Navier Stokes equation instead of the Advection Diffusion equation. One of t...

Hi all, I am trying to set up an Advection Diffusion problem where an ideal gas is flowing through a boundary at a given rate (mols/s) into an area of air. ElmerGUI shows 3 possible flux boundary types, Concentration flux, Mass Transfer Coefficient and External Concentration. It would seem that Mass...

Thanks for the reply Kevin. I corrected the node problem in my freecad sketch and re built the Elmer files. The problem persists. In addition, for some reason, the sif file now contains a Helmholtz solver that errors out at the very end of the run. It complains about not being able to find the frequ...

This is a simplified version of my problem. The actual problem is a Navier Stokes gas flow of 2 gasses mixing with complex shaped boundaries. I have not been successful with setting the boundary condition on the original problem. I would like to be able to break up the problem into separate "zo...