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heaving of a cylinder

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Old   May 6, 2013, 11:03
Default heaving of a cylinder
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Arun Krishnan.L.H
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Hi All,

I have posted this question before but got no replies. I request you to please guide me if you know anything about this problem.

I am trying to evaluate the hydrodynamic force on a cylinder which is heaving with an amplitude of 0.03 m( vertical which is y axis) and frequencies from 1-6 rad/s. The motion is sinusoidal with a velocity of 0.03 cos(wt). I am using morphing for this problem. The results I have attached is for 6.64 rad/sec. I have simulated the problem of swaying and successfully compared the results with experiments.

For heaving I have attached 3 force plots from STAR CCM+.
1. vertical force on the body with pressure only selected.
2. Surface integral of total force.
3. Surface integral of static force.

As per the results the static and total force seems to be the same. The vertical force is lower than what is obtained from 2 and 3. As per the manual Vertical force(pressure), is the surface force that acts on the wall. In that case i assume it must be giving me the total force with the static component?

Why is it then lesser than static and total? Why is the total and static forces equal to each other? How do I get the dynamic component?

The radius of the cylinder is 0.5 m.

Any suggestions would help me. I have gone through all the threads and could not find anything relevant.

total pressure.jpg

static pressure.jpg

vertical force.jpg

VOF.jpg

Please respond.

Regards
Arun
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Old   May 9, 2013, 10:47
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Arun Krishnan.L.H
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Can anyone give some suggestion pls?

Regards
arun
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