[mxylondon]

Dear foamers,

Has anyone used restraint 'tabulatedAxialAngularSpring' in dynamicMeshDict?

I appreciate that there is such option provided, but struggling with how to use this option properly.

It seems no examples can be found from anywhere yet.

Great thanks!

[wyldckat]

Quick answer: I've received the PM you sent me but I'm unable to give much of an answer.
If you could provide a simple test case, it would be a lot easier/quicker for me to solve the issues you're having with the configuration. Something as simple like a box with a coarse mesh...

The best I can do right now is tell you which parameters it's looking for, from the source code:

• https://github.com/OpenFOAM/OpenFOAM...ngularSpring.H
• https://github.com/OpenFOAM/OpenFOAM...ngularSpring.C

//optional, quote: "Reference orientation where there is no moment"
// it's meant to be a tensor and I believe this is the  conventional format for it, namely 9 elements (3x3) in the tensor.
/ /The  default is the identity matrix
referenceOrientation  (1 2 3 4 5 6 7 8 9);

// quote: "Global unit axis around which the motion is sprung"
axis (1 0 0); // X-axis in this example

// quote: "Spring moment interpolation table, depending on angleFormat"
//I'm not entirely certain if this is correct, without a test case
table
(
    //angle and scalar value, linear interpolation
   (0    0)
   (1.0 0.5)
   (10.0 100.0)
   (80.0 1000.0)
);

//two options: degrees or degree, radians or radian
//namely that it can handle the keyword in the singular or plural forms
//the idea is that this indicates the unit in which the interpolation table was defined
angleFormat   degrees;

// quote: "Damping coefficient (Nms/rad)"
// I'm not entirely certain if this is correct...
damping  0.01;

Regarding the units of the last value, check the source code for yourself: https://github.com/OpenFOAM/OpenFOAM...rSpring.C#L128 - I'm not entirely convinced if the units are correct...

And I don't know which OpenFOAM version you are using, so I went with version 5...

[mxylondon]

Oh my word, thank you so much Bruno. Feeling noticed by a King.

Based on Bruno's comments, now it is an update with my test over last night:

1. A constant moment can be added as a resistant to rotating things.
2. It can be done by designing a table for interpolation.
3. The restraint type to use is 'tabulatedAxialAngularSpring'.
4. The table can be written in a .dat file and put in case folder (top level).
5. The data structure for interpolation table is:

(
(angle1 moment1)
(angle2 moment2)
(angle3 moment3)
...
);

6. Entry 'angleFormat' must be defined.
7. Other parameters such as rotation axis etc should be set as that for other normal springs and dampers accordingly.

Hope the above could help others.