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March 3, 2011, 16:52 |
Impose transeint force
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#1 |
Senior Member
Henry Arrigo
Join Date: Jun 2010
Location: Italy
Posts: 100
Rep Power: 15 |
Hello,
How can I impose a sinusoidal force on a body. In the external force node there is no possibility to bind a Field function. What s your suggestions please? Thank you. Last edited by Henry Arrigo; March 3, 2011 at 17:51. |
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March 3, 2011, 16:54 |
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#2 |
Senior Member
Henry Arrigo
Join Date: Jun 2010
Location: Italy
Posts: 100
Rep Power: 15 |
any one can help me please?
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March 3, 2011, 23:29 |
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#3 |
Senior Member
Join Date: Jun 2009
Posts: 100
Rep Power: 16 |
If the field function is not available you need to write a macro.
A simple strategy is to record a macro where you set a value for the external force with a numeric value. Use this macro as a initial construct and instead of the numeric value replace it with your function. |
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March 4, 2011, 09:07 |
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#4 |
Senior Member
Henry Arrigo
Join Date: Jun 2010
Location: Italy
Posts: 100
Rep Power: 15 |
thank you
this is not gonna work since I need to impose a continuous force while this case would result in a discrete one. more over I want to come up with solution in a single run. |
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March 6, 2011, 23:28 |
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#5 |
Senior Member
Join Date: Jun 2009
Posts: 100
Rep Power: 16 |
Hi,
As long as you are using CFD for your simulation you cannot apply continuous force. Whatever you do, even if you manage to get your BCs via a field function you will be using a finite time step and hence your profile will always be implemented in discrete time steps and not in a continuous fashion as you have envisioned. So the only remedy to the above problem is to use a smaller time step while applying the acceleration profile. Hope you got that |
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March 7, 2011, 09:01 |
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#6 |
Senior Member
Henry Arrigo
Join Date: Jun 2010
Location: Italy
Posts: 100
Rep Power: 15 |
Hi,
Thank you Alastormoody. Did you mean applying acceleration to the fluid field? Did I get it right. In the wall node and in the Physics Conditions sub-node, there is an option which is named Tangential Velocity Specification. It has this possibility to use a field function as a vector field. Have you ever use that? I guess that could be a remedy too... Thanks. Henry |
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