Using ElmerSolver for Flow

Numerical methods and mathematical models of Elmer
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CarmeloLabadie
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Joined: 09 Jun 2021, 12:02
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Using ElmerSolver for Flow

Post by CarmeloLabadie »

Hi,

I am fairly new to FC and the integrated FEM workbench.

Structural analysis (simple beams/structures) via CalculiX/CCX is rather straightforward. However, I hit a wall when trying to set up a simple pipe and flow analysis.

When I search the forum I find several examples of Elmer files, all seem to solve fine and produce usable outputs. None of them is however a pure flow case, most are Heat/Flow.

When trying to simulate these examples solely for Flow I cannot achieve the same success (even checking the parameters each at a time).

Steps which I followed:

1. My test setup consists of a tube which reduces in diameter. The tube is split into an inner solid and outer (wall) solid. Both were combined as boolean fragments.

2. The large-diameter face of the inner solid is then given a flow velocity constraint in the X-axis direction.

3. Materials properties are added to outer and inner tubes.

4. Finally Gmesh is run to produce the mesh. For testing, a coarse mesh is used (once I figured how to do it, a refined mesh is to be used).

5. When running the Elmer Solver, I then get either errors or infinite looping.

5a. When I attribute 1 solid (the inner) to the Flow equation, I get an error stating "AttributeError: 'list_iterator' object has no attribute 'next'".
5b. When I attribute none or both solids to the flow equation, I get infinite looping of the Elmer solver, and I get Warning that there is no Viscosity parameter.

There doesn't seem to be a step by step tutorial on how to set up the Elmer solver (lots of references to the Elmer manual, but not really useful for me as I can't even get the solver started).

I must be making a stupid mistake in setting up the shape/solid etc..., so if anyone could give me a hint then that would be greatly appreciated.


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OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.23323 (Git)
Build type: Release
Branch: master
Hash: 512d5c6141aec52b6eecc67370336a28fde862a6
Python version: 3.8.6
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: Dutch/Belgium (nl_BE)
kevinarden
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Joined: 25 Jan 2019, 01:28
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Re: Using ElmerSolver for Flow

Post by kevinarden »

It would help if you could post the sif file and mesh, or gmsh file

I would recommend working through some of the flow tutorials.

https://www.nic.funet.fi/pub/sci/physic ... orials.pdf
annier
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Re: Using ElmerSolver for Flow

Post by annier »

Test examples using solely flow solver are also available in github repository of Elmer.
https://github.com/ElmerCSC/elmerfem/tr ... wResNoslip
https://github.com/ElmerCSC/elmerfem/tr ... lowResSlip
Anil Kunwar
Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice
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