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dynamicMeshDict update issue during run

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Old   March 31, 2013, 06:07
Default dynamicMeshDict update issue during run
  #1
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Dear All,

I'd like to know whether chagnes of dynamicMeshDict during run are refleted to the mesh motion or not, in pimpleDyMFoam.

In the source of pimpleDyMFoam.C, includiuons of "creatDynamicFvMesh.H" is conducted once before the time-stepping loop.
This is that we cannot run the solver in varing rotating speed ?

Thanks in advance,
waku2005
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Old   April 8, 2013, 05:46
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Further question.

In the solidBodyMotionFvMesh.C, dynamicMeshDict is defined as below.
MUST_READ_IF_MODIFIED option means that when dynamicMeshDict was updated manually, it would be re-read.
Even so I could not see such re-reading output and mesh change.
I'd like to know how to re-read the dict file during run.

Sincerely yours
waku2005

Quote:
dynamicMeshCoeffs_
(
IOdictionary
(
IOobject
(
"dynamicMeshDict",
io.time().constant(),
*this,
IOobject::MUST_READ_IF_MODIFIED,
IOobject::NO_WRITE,
false
)
).subDict(typeName + "Coeffs")
),
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Old   April 12, 2013, 04:18
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Daniel Witte
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Hello waku2005,

Maybe you look at my thread of last year:

AMI speed performance

I, too, wanted to change shaft speed during iteration and it works. You may alter this code to another time dependent shaft speed function. If your shaft speed is a reaction of some forces induced by the flow, this is a different story.

Hope this works for you,

Regards,

Daniel
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Old   April 15, 2013, 00:02
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Hi Daniel

Thanks a lot for your reply.

My objectives are
1. Dynamic update of rotational speed in dynamicMeshDict
2. From postProcessing data such as torque, do above update from a script or a new solver

The 1st one is what in your thread and I'll try it.

Sincerely
waku2005


Quote:
Originally Posted by danny123 View Post
Hello waku2005,

Maybe you look at my thread of last year:

AMI speed performance

I, too, wanted to change shaft speed during iteration and it works. You may alter this code to another time dependent shaft speed function. If your shaft speed is a reaction of some forces induced by the flow, this is a different story.

Hope this works for you,

Regards,

Daniel
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Old   April 15, 2013, 04:21
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Daniel Witte
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Hi waku2005,

Your are welcome. The post processing data is in a file called "forces" if you copy the code from my controlDic file. So, you only need to re-write dynamicmeshDic for each calculation step and relanch the calculation using the OpenFoam script. There are some examples in the tutorial using m4. I have used this in the past, because I was too lazy to retype the same command lines over and over again into the terminal. It is quite simple.

Regards,

Daniel
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Old   Today, 07:43
Default Changing of dynamicMeshDict during simulation in pimpleDyMFoam
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Rodrigo
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Dear waku2005,

Did you figure out if the change of dynamicMeshDict during simulation (run) affects the mesh motion in pimpleDyMFoam?

I also want to change it during my simulation, but I'm not sure if It will change the velocity of the mesh (mesh motion).

Best regards,
Rodrigo Correa
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Old   Today, 09:19
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Daniel Witte
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Dear Rodrigo,

I would not recommend this because what is changed is not the mesh motion (rotational velocity), but the mesh position. The rotational speed is converted into a rotational angle. For constant rotational speed, this is straight forward. If you overwrite the extsting rotational speed, the agitator will make a huge jump since the time history of the rotation is lost. You must determine the function rotational speed on time, convert this to rotational angle and alter the code as it reported within thread mentioned above.

Regards,

Daniel
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Old   Today, 12:06
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Rodrigo
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Dear Daniel Witte

Thank you so much for your reply!

I did the manual change of the angular velocity before read your answer and i couldn't see any difference between the previous and the actual one. I'm not sure that It really changes the mesh rotation speed during the simulation.

Best Regards,

Rodrigo
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