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April 14, 2011, 12:28 |
force on gmo with prescribed motion
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#1 |
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jiko
Join Date: Sep 2010
Posts: 31
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I am analysing vertical force of water on a vertically (z, axis of gravity) oscillating GMO. the amplitude and frequency of the gmo is prescribed.
now since it is oscillating in still water I thought the initial force would be 0 at 0 time. but it is not. could someone please explain why the vertical force is not zero at zero time. or is something wrong in my simulation setup ? thanks in advance. |
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April 26, 2011, 11:00 |
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#2 | |
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jiko
Join Date: Sep 2010
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Quote:
it's quite surprising that no one seems to have any idea of buoyancy |
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July 25, 2011, 14:45 |
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#3 |
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mohammad hossein shfiei
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July 25, 2011, 18:02 |
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#4 |
Senior Member
Jeff Burnham
Join Date: Apr 2010
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Force is calculated from acceleration (of the water on the object). If there is gravity, then the force is non-zero. If there is motion, then the force is non-zero. At t=0, when using the GMO harmonic oscillation model, acceleration is non-zero. Therefore, the initial state of the fluid is non-zero: although it is not 'in motion' (no advection is occurring), it is accelerating, correct? Therefore, the force on the GMO is also non-zero. Note that velocity works the same way, since it is also following a harmonic oscillation: GMO velocity at t=0 is not zero.
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July 29, 2011, 01:21 |
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#5 | |
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michael barkhudarov
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