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-   -   the 6-DOF embedded motion example ? (http://www.cfd-online.com/Forums/star-ccm/68195-6-dof-embedded-motion-example.html)

 uiui September 9, 2009 23:19

the 6-DOF embedded motion example ?

anybody have the example of 6-DOF embedded motion. pls explain it in detail or kindly send me the .sim file. Thanks very much...

 uiui September 11, 2009 00:50

nobody knows? this is all i can find from manual and release notes:

This latest version of STAR-CCM+ extends the recently introduced DFBI modeling capabilities by introducing the ability to simulate the movement of solid bodies using either embedded motion or mesh morphing. By enclosing the body to be studied in a spherical or cylindrical sub-domain, the embedded motion technique allows the simulation of extreme levels of rotation such as lifeboats falling into water or shipping containers slamming into the ocean. While the sub-domain is free to rotate without limitation, the rotation and translation of the outer fluid domain may be limited; ensuring robustness of solution without having to resort to time and resource consuming re-meshing techniques.

Embedded motion (the moving body is enclosed in a sphere or a cylinder and attached via the sliding interface to the remaining part of the grid)

The 6-DOF Embedded Motion model involves a floating object in a sphere. The simulation includes a sliding internal interface between the sphere and the rest of the mesh, and the sphere rotates. This approach allows for larger rotating angles while creating a fine mesh only within the sphere. This is an alternative to a higher resolution for the entire mesh, which would be more computationally expensive.

So the question is:
1. the subdomain should create a region seperately or inside the whole region?
2. how to define a sliding internal interface.
3. how to define the relation between rigid body and sliding interface?

I am stuck on the problem and appreciate any idea from you. Thanks in advance !

 Ale_galleria October 8, 2010 09:35

Up. I have the same dubs. Help me, thank you.

 naimishharpal May 5, 2011 19:21

DFBI Emebedded Motion

1. the subdomain should create a region seperately or inside the whole region?
Ans: Both the domains must belong from two separate regions. The spherical region (which includes boat...) has to be specified with 'DFBI Embedded Motion', whereas the outer domain with Stationary. Since, common fluid passes, same Physics1 has to selected for both regions.

2. how to define a sliding internal interface.

3. how to define the relation between rigid body and sliding interface?
Ans: Once you define your rigid body as 'DFBI', it will behave as per DFBI Embedded Motion, and I think it doesn't require any 'relation' with interface. The 6-DOF should calculate the motion automatically, and the corresponding fluid properties will be exchanged at the interface.