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6 DOF objects colliding with walls

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Old   December 4, 2010, 04:04
Default 6 DOF objects colliding with walls
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Ed Moses
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Hellow All,

My name is Ed Moses and I am new to Flow 3D (though I have CFD experience with other codes). I am setting up a problem involving 6 degrees of freedom objects freely moving with the flow in a confined space. The bodies are nearly neutrally buoyant and there is no free surface. What happens is the sometimes (not all the time) one of the bodies will penetrate the wall of the vessel and go outside the flow field alltogether. The confining vessel is defined as a component (from a .stl file) with given collision properties. Collision model is activated as well as gravity. The 6DOF bodies are also imported as separate components from .stl files and collision properties are defined for them.

Anybody can give me an idea what I did wrong to have these objects penetrate the solid walls of the confining vessel?

Many thanks and best regards,
Ed Moses
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Old   December 5, 2010, 08:37
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Yang Yue
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Does your .stl file has thin wall? Once I got the similar problem if the stl file has thin part while the mesh is not fine enough.

Yang
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Old   December 5, 2010, 11:02
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Ed Moses
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Quote:
Originally Posted by therockyy View Post
Does your .stl file has thin wall? Once I got the similar problem if the stl file has thin part while the mesh is not fine enough.

Yang
Dear therockyy,

Many thanks for your swift answer. My .stl is actually the fluid domain (complement) and has zero thickness walls. I see the problem now and will change the .stl to be the actual solid, so that the wall will have a thickness.

Many thanks and best regards,
Ed Moses
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Old   December 7, 2010, 09:37
Angry 6 DOF objects colliding with walls
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Boris Huber
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Hi,
The collision model does not work properly when objects collide very slowly - Flow Science knows that but it will be fixed somewhat later.

Greatings
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