How to define 2 grids to move the inner object?
 

problem description:

I want to simulate a case with a moving object.
Can somebody help me and give some ideas for the principal approach.

http://img832.imageshack.us/img832/6173/testqrx.jpg

It should be similar to this project
http://www.youtube.com/watch?v=S-p0uau9nGA

I would solve it in this way:

1. Design the grid of the big rectangle (with a rectangle-shaped hole in the middle)


2. Design grid of the small rectangle with the object in the middle
3. Write a UDF for movement
4. Use the fluent funktion to reshape the grid during the simulation. (dynamic meshing)


My questions:

1. Do I have to divide the 2 rectangles in the mesher or in the geometry-builder?
When I use the Designmodeler, draw the 2 rectangle and the object, click then on "surface from sketches", the space between inner rectangle and circle is empty. And I don't know how to avoid that. Some Ideas?
http://img228.imageshack.us/img228/2064/unledbu.jpg
2. Are there any faults in my plan?
3. Any suggestions to improve it?

These are separate overlapping grids? I have never actually solved one of these, but I would guess that you probably need to mesh them separately, not as a single model. Then overlap the mesh models in the solver.

The trick is
1. to make TWO sketches.
2. splitface

That will get you your nested box structure, but won't allow the one mesh to fall thru the other... Or do you mean to morph th outer box?

Sorry, I thought you planned for overlapping grids.

mesh morphing
 

I think that the problem can be faced using the mesh morphing tool RBF Morph (www.rbf-morph.com).

http://rbf-morph.com/images/rnd_imag...rph-ws-200.gif

I have looked at a variety of morphing tools and none are more powerful or better integrated into Fluent than RBF-Morph...

Simon