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falling ball in water

Posted Jan 17, 2011, 8:21 a.m. EST Fluid & Heat, Structural Mechanics Version 4.0a 3 Replies

Rose
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Hi
I want to simulate falling of a Aluminum ball in water. Ball initially is 1 meter above the surface of water.

is this possible with Comsol? could you please guide me?

Thank you
3 Replies Last Post Jan 17, 2011, 9:53 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 17, 2011, 9:36 a.m. EST
Hi

I believe with a FSI (fluide structure interaction) module it should work :

model the water & the ball (ideally starting inside the water, as if not you need to try special tricks à la "level set", not even sure it works). You add some body load from gravity, use a time series/transient solver, that should be it

probably you could start in 2D-axi to make the model simpler and quicker so solve.

Note, improve somewhat the default initial condition = 0, that helps a lot on the solving time and convergence chances

And use if possible v4.1 it has a better documentation and is smoother than the early version 4.0, particularly for cfd

--
Good luck
Ivar
Hi I believe with a FSI (fluide structure interaction) module it should work : model the water & the ball (ideally starting inside the water, as if not you need to try special tricks à la "level set", not even sure it works). You add some body load from gravity, use a time series/transient solver, that should be it probably you could start in 2D-axi to make the model simpler and quicker so solve. Note, improve somewhat the default initial condition = 0, that helps a lot on the solving time and convergence chances And use if possible v4.1 it has a better documentation and is smoother than the early version 4.0, particularly for cfd -- Good luck Ivar
Rose
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Posted: 1 decade ago Jan 17, 2011, 9:46 a.m. EST
Thanks a lot for your reply.

is it possible to model surface between air and water ? I'm new to Comsol. would you please describe more?

I have attached the simple model. I am eager to see surface change during the process.

Gray : Air
Green : Ball
Blue : Water


Thanks
Thanks a lot for your reply. is it possible to model surface between air and water ? I'm new to Comsol. would you please describe more? I have attached the simple model. I am eager to see surface change during the process. Gray : Air Green : Ball Blue : Water Thanks

Attachments:

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Jan 17, 2011, 9:53 a.m. EST
Hi

certainly possible, but that's the trickyest example, i.e. how to define the contact and change in topology ? probably one need to try with a level set methode, but it means formula tweaking, and fun, but too much to do for now and here, for me :)
Sorry cannot do better, but try already a falling ball in a tube of water, once you have that running, you should also have some good clues how to continue

--
Good luck
Ivar
Hi certainly possible, but that's the trickyest example, i.e. how to define the contact and change in topology ? probably one need to try with a level set methode, but it means formula tweaking, and fun, but too much to do for now and here, for me :) Sorry cannot do better, but try already a falling ball in a tube of water, once you have that running, you should also have some good clues how to continue -- Good luck Ivar

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