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rigid body motion with constant velocity

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Old   August 12, 2014, 17:43
Default rigid body motion with constant velocity
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aliali
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Hi

I need to put a constant velocity on my rigid body in one direction.
but I don't know where and how I have to do it?

thanks
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Old   August 12, 2014, 18:56
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Glenn Horrocks
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Is it an immersed solid or a moving mesh rigid body?

Does the degrees of freedom controls do what you want?

If you have a rigid body in constant motion then it is not really rigid body motion and really just a moving mesh model. So you could just model it with moving mesh (or a pre-defined source term)
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Old   August 13, 2014, 05:59
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Thanks.
I put one degree of freedom for it so It moves only in one direction.

I first simulate the body under gravity force and I got results but now I want to simulate the same body with a constant velocity (3 m/s) in the same direction.

I defined a rigid body and a wall condition for the surfaces of my rigid body.

In rigid body options I have an initial velocity and in wall condition's option I have specified displacement ans specified location. I tried to set specified displacement as 3[m]*t but it doesn't work.

how can I say to my rigid body that moves all the time in 3 m/s?
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Old   August 13, 2014, 06:07
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Try defining an initial velocity of 3m/s and give it a massive mass. Then the fluid forces acting on it will not affect it.
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Old   August 14, 2014, 14:50
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Thanks ghorrocks
I have another question. I defined wall condition for the surfaces of my rigid body and I need to calculate the velocity of the wall. I want to check that the wall is moving at 3 m/s .
In fact how can I know the velocity of the wall at every moment and acceleration of that?
Thanks
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Old   August 14, 2014, 18:30
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Have a look at the reference manual. It lists all the variables available on rigid bodies.
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Old   August 20, 2014, 10:53
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Quote:
Originally Posted by ghoroobeaakhar View Post
Thanks ghorrocks
I have another question. I defined wall condition for the surfaces of my rigid body and I need to calculate the velocity of the wall. I want to check that the wall is moving at 3 m/s .
In fact how can I know the velocity of the wall at every moment and acceleration of that?
Thanks

by output setting in cfx-pre or timestep selector in post or chart(transient xy....)
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Old   December 23, 2014, 15:52
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Quote:
Originally Posted by ghorrocks View Post
Try defining an initial velocity of 3m/s and give it a massive mass. Then the fluid forces acting on it will not affect it.

Is it initial velocity set in Dynamic Mesh Zones/ Motion Attributes/Center of Gravity Velocity ?

Im working under Fluent
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Old   December 23, 2014, 17:28
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This is the CFX forum. Try the fluent forum.
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