[eagle_001]

Hello, everyone!

In the external flow field, my model can be divided into two parts, namely, Part A and Part B. The motion of Part A is defined in global coordinate, while the motion of Part B is defined relative to Part A.

Firstly, I treat both of the two parts as rigid body, and use two DEFINE_CG_MOTION macros in udf to define their motions. And define Part A first in the Dynamic Mesh Zone dialogue, then define Part B, enable the relative motion and specify the Relative Zone as Part A. These steps are described in the Uers guide. I succeeded in doing this.

After that, I treat the Part B as flexible body, and use CG_MOTION and GRID_MOTION to define the motion of Part A and Part B, respectively. In the GRID_MOTION, NODE_X(v) and NODE_Y(v) macros are used to specify the relative deformation. But when I define Part B's motion in the Dynamic Mesh Zone dialogue, I find there is no Part A can be selected in the Relative Zone box.

In the Uers guide, I found a piece of description as follow: you must specify the movement/deformation in you UDF using NODE_COORD_NEST rather than specify the final coordinates.
I search the NODE_COORD_NEST macro in the UDF manual, only one place is found and no example is shown.

So if anyone has ever defined momvement/deformation relative to a rigid body motion and could give me any help?
Thanks a million!