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Newton's bucket experiment

Posted Aug 3, 2012, 4:44 a.m. EDT Fluid & Heat, Geometry, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3 6 Replies

Marcel van Beek
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Dear reader,

I am look to simulate Newton's bucket experiment. I am trying to simulate one cylindrical object of water. And have the wall rotate around the cylinders axes. This should excert a drag force on the fluid because I have the no-slip condition box checked. But I can't find a way to have the wall displace it self around the central axes.

I am just going about it all wrong? Or did I miss something you might point out to me?

Please help me
6 Replies Last Post Aug 3, 2012, 9:27 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Aug 3, 2012, 5:08 a.m. EDT
Hi

I believe one way is to use the rotary fluid set up physics, check the model library for the examples. But normally I believe you can define a velocity for a boundary directly in the CFD, the only thing is that you need to define a cylindrical coordiante and define the rotation accordingly in the phi direction.

--
Good luck
Ivar
Hi I believe one way is to use the rotary fluid set up physics, check the model library for the examples. But normally I believe you can define a velocity for a boundary directly in the CFD, the only thing is that you need to define a cylindrical coordiante and define the rotation accordingly in the phi direction. -- Good luck Ivar
Marcel van Beek
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Posted: 1 decade ago Aug 3, 2012, 5:20 a.m. EDT
thanks for repleying

I did defined a cylindrical coordiante and defined the rotation in the phi direction but can't find a way to add a velocity to any boundary (the walls). I am only able to add a velocity to a object.
thanks for repleying I did defined a cylindrical coordiante and defined the rotation in the phi direction but can't find a way to add a velocity to any boundary (the walls). I am only able to add a velocity to a object.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Aug 3, 2012, 7:06 a.m. EDT
Hi

I'm not by my COMSOL WS so I cannot check myself, but perhaps you might add a subnode to the wall node of the type velocity, and ceck the help files. It could be that its related to some of the additional modules

--
Good luck
Ivar
Hi I'm not by my COMSOL WS so I cannot check myself, but perhaps you might add a subnode to the wall node of the type velocity, and ceck the help files. It could be that its related to some of the additional modules -- Good luck Ivar
Jeff Hiller COMSOL Employee

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Posted: 1 decade ago Aug 3, 2012, 8:33 a.m. EDT
See www.comsol.com/showroom/gallery/616/
Note that to model this in 2D axi, you will need the swirl flow interface that is part of the CFD Module.
See http://www.comsol.com/showroom/gallery/616/ Note that to model this in 2D axi, you will need the swirl flow interface that is part of the CFD Module.
Marcel van Beek
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Posted: 1 decade ago Aug 3, 2012, 9:01 a.m. EDT
Sorry I was blind didn't look in the right place. I found what you were talking about in boundary conditions. But I don't get an option to have the moving wall condition expressed in cylindrical coordinates. Is there a way to write the x en y components as tangental velocity
Sorry I was blind didn't look in the right place. I found what you were talking about in boundary conditions. But I don't get an option to have the moving wall condition expressed in cylindrical coordinates. Is there a way to write the x en y components as tangental velocity
Marcel van Beek
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Posted: 1 decade ago Aug 3, 2012, 9:27 a.m. EDT
I have found sliding wall and that was exactly what I needed. Thanks for any help!
I have found sliding wall and that was exactly what I needed. Thanks for any help!

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