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June 17, 2018, 02:15 |
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#21 | |
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As you have already determined, the position is consistent after restarting Fluent, but what about ? |
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June 17, 2018, 02:19 |
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#22 | |
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Please don't go out of your way to do this but. If you have some time to kill only then do it cos it will take a day easily. That was very kind of you to offer to simulate it yourself. |
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June 17, 2018, 02:20 |
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#23 |
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June 17, 2018, 02:24 |
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#24 |
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I have not used the Six DOF solver before, and I do not have this version of ANSYS installed to have a quick check. Is there any mention in the Fluent guides? Otherwise have a look around the GUI?
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June 17, 2018, 02:30 |
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#25 |
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Yea, will do that. I have restarted a simulation for another case to see if this happens in that too. If it does, then next time I will use the UDF approach. But honestly, I would expect the same thing to happen there too cos the UDF will only have the mass, spring constant and 1dof as parameters, not initial equilibrium position.
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June 17, 2018, 02:47 |
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#26 | |
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If you only want a single DOF such that the restoring force of the spring acts purely in the y-direction, then the force on the cylinder could be calculated with: Code:
force = -k*(DT_CG(dt)[1] - x_equilibrium[1]); Note: remember that indexing in C starts from zero instead of one, so DT_CG(dt)[1] corresponds to the second spatial coordinate (y for Cartesian). |
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June 17, 2018, 02:51 |
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#27 |
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June 17, 2018, 04:36 |
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#28 | |
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June 17, 2018, 04:53 |
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#29 |
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Well, this result is consistent with what we consider the problem to be: that the equilibrium position of the spring is being reset on restarting Fluent. I would expect (or at least hope) that using the UDF would solve this issue, and would also give you greater control and transparency on what you are actually solving.
Yes, a 3-D simulation would be much more computationally expensive. Remember to optimise your mesh and you could also start with an initial condition based on your 2-D result to help reduce the time it takes for the flow/oscillations to fully develop. |
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June 17, 2018, 05:02 |
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#30 | |
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June 19, 2018, 07:50 |
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#31 |
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March 4, 2021, 01:37 |
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#32 |
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dynamic mesh, restart problem, viv |
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