Learning Forum

[Hunter Dennison]

I'm attempting to run a CFD-6DOF transient simulation with multiple oversets. One of the oversets is governed by the dynamic mesh 6DOF solver. However, I want to link the motion of the other fluid wake overset mesh to that of the first one. However, only translation not rotational motion. I was wondering if I could use Define_Grid_Motion to move a whole fluid domain and BCs (Overset) without imparting a fluid flow (I only want to move the grid). If this isn't the ideal method, then what method if any are capable of the desired results.

[Federico]

Hello Hunter, 

You can have Overset 2 (wake mesh) follow the motion of Overset 1 (with 6DOF) by assigning Rigid body motion to the wake mesh as Passive 6DOF. This means that forces will not be calculated on the wake mesh but it will follow the resulting motion of Overset 1. However, this will have the same degrees of freedom as your Overset 1 mesh (i.e. will include rotational freedom).

If you have access to the translational velocity that you want to assign to Overset 2, I would use DEFINE_CG_MOTION instead of GRID_MOTION. The latter is used when there is some deformation involved and hence you want to prescribe motion on a node basis.

[Federico]

You can find some useful information on 6DOF here: 12.6. Using Dynamic Meshes (ansys.com)

[Hunter Dennison]

I managed to figure it out the night I posted and forgot to take down the post, but thanks