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July 11, 2019, 04:22 |
User guide for dynamicMeshDict
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#1 |
Senior Member
Sita Drost
Join Date: Mar 2009
Location: Arnhem, The Netherlands
Posts: 227
Rep Power: 18 |
Hello all,
Is anybody aware of the existence of an up-to-date user guide/tutorial on the use of dynamic mesh in OpenFOAM 6? I'm trying to use the DTCHullMoving tutorial as a basis for my own simulations, but I'm not quite sure about the meaning of some parameters in dynamicMeshDict: - I'm guessing "inertia" represents the inertia tensor, with only 6 moment of inertia values because of symmetry, in the order Ixx, Ixy/yx, Ixz/zx, Iyy, Iyz/zy, Izz. Is that correct? - What exactly does "transform" mean/do? It looks like it moves centreOfMass to the position of the centre of mass/rotation, but why not define centreOfMass at the correct position directly then? - Regarding "innerDistance" and "outerDistance": how are these distances measured, i.e. relative to what point? Any help would be appreciated! Sita Last edited by sita; July 11, 2019 at 07:17. |
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July 12, 2019, 06:37 |
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#2 | |||
Senior Member
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Hello Sita,
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Hope this helps. Regards, Tom |
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July 12, 2019, 08:05 |
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#3 |
Senior Member
Sita Drost
Join Date: Mar 2009
Location: Arnhem, The Netherlands
Posts: 227
Rep Power: 18 |
Hello Tom,
Thanks a lot for your replies, things are getting much clearer for me now! Cheers, Sita |
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October 12, 2020, 13:57 |
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#4 |
Member
Sachin
Join Date: Aug 2014
Location: India
Posts: 84
Rep Power: 12 |
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October 13, 2020, 03:27 |
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#5 |
Senior Member
Sita Drost
Join Date: Mar 2009
Location: Arnhem, The Netherlands
Posts: 227
Rep Power: 18 |
Hi Sachin,
I never actually checked the equations I'm afraid, but I'd say it's the mass moment of inertia; the area moment of inertia wouldn't make much sense for a 3D object. Also, in the Wiki the momentOfInertia is listed under Mass Properties: https://openfoamwiki.net/index.php/P...onSolverFvMesh. And finally, if you go through this forum, you'll notice that you're not the first one to wonder: moment of inertia in dynamicMeshDict Hope this helps, Sita |
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December 20, 2020, 16:39 |
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#6 |
New Member
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March 13, 2021, 13:20 |
Mass property
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#7 |
Member
Deutschland
Join Date: Sep 2020
Posts: 69
Rep Power: 6 |
Hey,
I am trying to simulate a ship flow. I have few questions regarding dynamic mesh. Hope someone can help. Its urgent 1. in DTCHull case entire ship is considered in the snappyHexDict even though one half is simulated. Does this not affect the parameters in the entire case setup? So is it fine if I use my entire geometry rather than cutting the geometry into half and then using it? If I use the entire geometry wall all think should I pay attention to? 2. In another thread I asked if I am using the half geometry should the mass properties be of the half geometry and I was told yes. Then if so doesn't it affect the centre of mass and moment of inertia? 3. why is the rhoInf in the dynamic mesh 1. should it not be the density of the ship (mass/volume). I have the weight for my geometry (77 kg) and I got the volume using the Solidwork. 4. The moment of inerta. there are 3 moment of inertia a. Principal axes of inertia and principal moments of inertia: ( kilograms * square meters ) Taken at the center of mass. b.Moments of inertia: ( kilograms * square meters )Taken at the center of mass and aligned with the output coordinate system c. Moments of inertia: ( kilograms * square meters ) Taken at the output coordinate system. My guess for the moment of inertia was about the center of mass since that is what asked in the dynamic mesh. Bot I try to clarify it using Solidwork, I am not getting the same moment of inertia nor mass using the rhoInf as 1 so I tried to find the density using the mass in the dynamicMeah and the volume I got from the software. But I still don't have answers Please please help. I am lost and out of ideas Kind regards vava10 |
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April 20, 2021, 07:32 |
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#8 | |
Member
Sachin
Join Date: Aug 2014
Location: India
Posts: 84
Rep Power: 12 |
Quote:
Thank you for the reply. I have tried using the surfaceInertia tool in openfoam to calculate the value for the dtchull form in openfoam tutorial. But the values obtained using the tool does not match with the values in dynamicmeshdict inthe tutorial. Did anybody try this? With Regards, Sachin M |
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May 18, 2021, 22:01 |
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#9 |
New Member
RICHARD LEONEL VASQUEZ MEZA
Join Date: Jun 2018
Location: PERU
Posts: 4
Rep Power: 8 |
hello.. maybe those videos can you help in order to found the properties of the body.
also the center of pressure. https://www.youtube.com/watch?v=0gmVWp38KLo https://www.youtube.com/watch?v=-MXho20qm1k&t=2s |
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December 26, 2021, 13:37 |
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#10 | |
Member
Join Date: Jan 2017
Posts: 71
Rep Power: 9 |
Quote:
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