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How to use sixDoFRigidBodyDisplacement?

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Old   February 25, 2013, 12:36
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Luca Bonfiglio
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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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Old   August 8, 2013, 07:55
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sarvagy
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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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Old   August 17, 2013, 08:24
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Md. Naimul Haque
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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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Old   August 17, 2013, 08:29
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Md. Naimul Haque
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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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Old   January 2, 2014, 07:30
Post RBF vs 6DOF
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arash mahboubi
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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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Old   January 5, 2014, 10:07
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Take a look at he pimpleDyMFoam tutorial called wingmotion.
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Old   January 13, 2014, 07:08
Default sixdofrigidbodydisplacement
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mohammadreza sattari
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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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Old   January 20, 2014, 06:56
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mohammadreza sattari
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Dear arash, please help me to use RBFmotion solver...
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Old   January 20, 2014, 11:51
Default RBF motion
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arash mahboubi
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Quote:
Originally Posted by mr.sattari View Post
Dear arash, please help me to use RBFmotion solver...
mr sattari
You should refer to: http://repository.tudelft.nl/assets/...daa1b2/bos.pdf
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Old   March 12, 2014, 06:45
Default sixdofrigidbody
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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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Old   July 18, 2014, 18:31
Default sixDoFRigidBodyMotion for multiple bodies
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kumar
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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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Old   December 3, 2014, 10:38
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ok
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Quote:
Originally Posted by kumar2 View Post
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

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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Old   December 3, 2014, 14:54
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kumar
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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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Old   June 18, 2015, 10:09
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sagar gurnani
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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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Old   July 19, 2015, 08:03
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Fei Fan
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Quote:
Originally Posted by kumar2 View Post
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
Hi Kumar:
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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