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#21 |
New Member
Luca Bonfiglio
Join Date: Oct 2011
Posts: 9
Rep Power: 14 ![]() |
Hi Mr. Naimul Haque,
I'm sorry for the late answer. I tried to use the fixedPlane option and it seems that it constrains a point that is in a plane to stay in that plane. That means that if roll movement has to be fixed (rotation around x axis -1 0 0-), the plane whose normal is (0 1 0) has to be fixed. In such a way the only movement will be pitch (around y axis) because it won't be possible to have yaw (this movement will move a point in xz plane out from this plane). Do you agree?? What do you mean with dealing with the constrain tensor? I still haven't faced any problem like that regards Luca |
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#22 |
New Member
sarvagy
Join Date: Jun 2013
Location: iit kanpur
Posts: 2
Rep Power: 0 ![]() |
hi people
i am new to openfoam can anyone tell me what should be the entries in pointdisplacement file so i i get a free rotational and translation motion ie: full six dof motion |
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#23 |
New Member
Md. Naimul Haque
Join Date: Jan 2013
Posts: 14
Rep Power: 13 ![]() |
Dear Luca Bonfiglio,
Sorry, I just have seen your post, long time I am not using. I have forgot. Now I am running static cases. After finishing static cases, I would start dynamics cases. Hope I can help you on that time. |
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#24 |
New Member
Md. Naimul Haque
Join Date: Jan 2013
Posts: 14
Rep Power: 13 ![]() |
Dear Flash,
I forgot, long time I am not using. Sorry. If I can remember something, I would let you know. |
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#25 |
Member
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Hi
I've used the RBFmotion for my flapping airfoil (rotation and translation). But the running time was too long.(50 days with 40000 cells).That's why I decided to use the sixDofRigidBodyDisplacement.But I am not familiar with its parameters. Does anyone have a pdf about it?How do I apply two degrees of freedom for airfoil?Is there a connection between the RBF and sixDof? |
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#26 |
New Member
Join Date: Mar 2009
Posts: 21
Rep Power: 18 ![]() |
Take a look at he pimpleDyMFoam tutorial called wingmotion.
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#27 |
New Member
mohammadreza sattari
Join Date: Oct 2013
Posts: 3
Rep Power: 12 ![]() |
Dear foam users,hi
i am simulating the flow around a rotating cylinder with sinusoidal translation simulantaneously... I need a good bounadry condition such as "sixdofrigidbodydisplacement" but i can not use it,because of complexity ![]() can anyone help me please? ![]() |
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#28 |
New Member
mohammadreza sattari
Join Date: Oct 2013
Posts: 3
Rep Power: 12 ![]() |
Dear arash, please help me to use RBFmotion solver...
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#29 |
Member
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mr sattari
You should refer to: http://repository.tudelft.nl/assets/...daa1b2/bos.pdf |
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#30 |
New Member
Join Date: Mar 2014
Posts: 1
Rep Power: 0 ![]() |
Hi Foamers,
I want to simulate the flow around a ship-model with free trim (rotation around y-axis) and heave (translation in z-axis-direction) with interdymfoam. My grid represent the dynamic position of the ship, so the model is in a given trim- and heave-position. Makes it sense to fix all dof until there will be a full developed flow and after that unfix the motion around y-axis and in z-axis-direction. If yes, how i fix all dof? With over-constraining? Or is it a better way to start the simulation directly with free trim- and heave-motion? Thanks for help. Regards Conrad |
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#31 |
Senior Member
kumar
Join Date: Mar 2009
Posts: 112
Rep Power: 17 ![]() |
Hi All,
I have a question on linearSpring restraint in sixDoFRigidBodyMotionRestraint when the anchor is on another moving body. For example in the default linearSpring.C the r vector is calculated as : vector r = restraintPosition - anchor_; // anchor is fixed. How can this code be modified such that anchor is on another moving body? In other words, how can the sixDoFRigidBodyMotionRestraint class be modified to acquire the, say the centreOfMass of another floating body. Thanks in advance Kumar |
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#32 | |
Senior Member
ok
Join Date: Oct 2013
Posts: 346
Rep Power: 13 ![]() |
Quote:
Dear Kumar, did you find answer for your question? I'm working in free vibrating cylinder and I'm struggling in pointDisplacement file. I'm still looking for answers of some questions for using sixDoFRigidBodyDisplacement. If you could help me that would be grateful. Kind regards Maimouna |
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#33 |
Senior Member
kumar
Join Date: Mar 2009
Posts: 112
Rep Power: 17 ![]() |
Hi Maimouna,
At this point there is no way to do this , i.e, make one body recognize center of mass etc of another body. You need to rewrite the forces library extensively to do this. Sorry I cannot be of much help here. Regards Kumar |
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#34 |
New Member
sagar gurnani
Join Date: Jun 2015
Location: surat gujarat
Posts: 6
Rep Power: 11 ![]() |
Hi foamers,
I would like to know what constrains should I put if I need free motion in all 6 direction?? Thanks |
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#35 | |
Member
Fei Fan
Join Date: Jun 2013
Location: NanJing, China
Posts: 54
Rep Power: 13 ![]() |
Quote:
In the waves2Foam topics, you added the density term into the turbulence model for simulation wave breaking. I want to research the undertow under the spill breadking wave. when simulatiom i have found that the wave elevation decay. so I think it's because the density term is not included in the turbulence model, and i don't know how to added the density term into the turbulence, can you help me? Thanks. best regards Fanfei |
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#36 |
New Member
anand sudhi
Join Date: Sep 2015
Posts: 16
Rep Power: 11 ![]() |
I need help in specifying fixedPlane constraint in dynamicMeshDict for a 2D case in the x-y plane with pitching motion and translation in x and y
Is this entry the correct way fixedPlaneXY { sixDoFRigidBodyMotionConstraint fixedPlane; fixedPlaneCoeffs { refPoint $centreOfMass; direction (0 0 1); //normal direction to plane } } I am solving an overset mesh problem and use the sixDOFMotion to slide one mesh over the other. I need to constraint the motion in the x-y plane. And using fixedAxis seems to not update my rotation as the axis vector (0 0 1) does not lie in my moving mesh. Thank you |
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#37 |
Member
Gautami Erukulla
Join Date: Mar 2009
Posts: 71
Rep Power: 17 ![]() |
P { margin-bottom: 0.08in; } Dear All,
I am trying to create a “userdefined.so” for defining the 'sixDoFRigidBodyMotionRestraint' condition, by modifying the file 'linearSpring.C'. In the file it shows that the value 'restraintForce' is calculated. I would like to read the value for 'restraintForce' from an input file. Can this be done by using #include option? What is the input file format for that and how to assign the value read from the input file to restraintForce. Your suggestions and guidance will be highly helpful. Thank you Most&More Gautami Erukulla. |
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#38 |
Senior Member
Join Date: Jul 2011
Posts: 120
Rep Power: 15 ![]() |
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#39 | |
New Member
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Quote:
Dear Gautami, Did you manage to change the restraintForce in linearSpring.C file? If yes, please share how did you do that. I am actually looking to modify the restraintForce equation by adding the external force, but haven't succeeded yet. Thanks. Best, Sachin |
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#40 |
Member
Gautami Erukulla
Join Date: Mar 2009
Posts: 71
Rep Power: 17 ![]() |
Dear Sachin,
I found the following paper, http://www.tfd.chalmers.se/~hani/kur...JP_peered1.pdf wherein the details to modify the restraint force in linearSpring.C file are explained with an example. I worked accordingly and was able to modify with out issues. I am hoping this paper would be useful for you too and works out.Thanks. Most&More, Gautami Erukulla. |
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Tags |
contstraints, restraints, sixdof, sixdofrigidbody |
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