## About how-to set surface tension in Level Set Method

Numerical methods and mathematical models of Elmer
SagittariusChiron
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### About how-to set surface tension in Level Set Method

Hellow.

I am a beginer of the Elmer in Japan and started the Elmer only one month ago.

I am interested in a behavior of a free surface, which is in the condition of steady flow and has surface tension coefficient.

I have found two relevant discussion in this post:

viewtopic.php?f=3&t=3303&p=10533&hilit= ... ion#p10533

viewtopic.php?f=3&t=808&p=10690&hilit=s ... ion#p10690

I read those,and I undestand that the "surface tension coefficient" means the "curvature coefficient " in levelsetcurvature solver.

Now, I already done some tutorials.
"Axisymmetric coating prosess" as 10th tutorial of Elmer non-GUI Tutorials (August 3,2020)is useful for me. But, this tutorial is included in only free-suface-reduced and not included in level-set-method and surface-tension-coefficient.

Could you please teach me below,

Where is the tutorial about level set method and surface tension coefficient ?
or
Where is another tutorials from Elmer GUI Tutorials and Elmer non-GUI Tutorials ?
raback
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### Re: About how-to set surface tension in Level Set Method

Hi

Tutorials exist only for a small fraction of all the capabilities. Levelset has not really been in the focus lately. Probably the only test case with surface tension is the test case "LevelsetFallingDrop". Additionally I would refer to the Models Manual. There are also some other levelset cases among tests but no other includes surface tension.

-Peter
SagittariusChiron
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### Re: About how-to set surface tension in Level Set Method

I got the test case "LevelsetFallingDrop",and executed blow comand in Windows10:
- ElmerGrid 1 2 square.grd
- elmerf90 DropStuff.f90 -o DropStuff.dll
- ElmerSolver

ELMER SOLVER (v 9.0) STARTED AT: 2021/01/12 22:36:26
ParCommInit: Initialize #PEs: 1
MAIN:
MAIN: =============================================================
MAIN: ElmerSolver finite element software, Welcome!
MAIN: This program is free software licensed under (L)GPL
MAIN: Copyright 1st April 1995 - , CSC - IT Center for Science Ltd.
MAIN: Version: 9.0 (Rev: Release, Compiled: 2020-11-11)
MAIN: Running one task without MPI parallelization.
MAIN: =============================================================
ERROR:: ElmerSolver: Unable to find ELMERSOLVER_STARTINFO, can not execute.
STOP 1

There is a file "ELMERSOLVER_STARTINFO.txt" in a folder "ELMERSOLVER_STARTINFO".
Could you please teach me how to run the test case.
kevinarden
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### Re: About how-to set surface tension in Level Set Method

ELMERSOLVER_STARTINFO is a text file that contains the name of the sif file to be run

It isn't required to be used you can do

ElmerSolver mycase.sif

to specify the sif file

although the test case looks to be correctly set up
raback
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### Re: About how-to set surface tension in Level Set Method

The "ELMERSOLVER_STARTINFO" is a bare file. You probably introduced the .txt suffix yourself when copying the file into Windows.
kevinarden
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### Re: About how-to set surface tension in Level Set Method

"ELMERSOLVER_STARTINFO.txt" windows wants to add a suffix to every file, but depending on options does not always show the suffix. This file name has no suffix, but it is a text file. If your suffix display option is off you will not see that it has a suffix, which it should no have one.
SagittariusChiron
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Joined: 11 Jan 2021, 05:36
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### Re: About how-to set surface tension in Level Set Method

Thanks !
I succeeded to run the test case "LevelsetFallingDrop".

Windows add a suffix "txt" to a file ELMERSOLVER_STARTINFO, but I don't want it.

By the way
this "LevelsetFallingDrop" case means the VOF method, unlike that "Axisymmetric coating process" case means the ALE(Arbitrary Lagrangian-Eulerian) method. And, I did not find "surface tension coefficient" in the "drop.sif" file.

I want to add the surface tension effect to free surface which transformed with ALE method.

Is there some hint for it ?
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