My geometry is like that. The clearance is very less

the circle represents your rotating solid?

Yes my circle is rotating and solid

This is typical reason why you need to post picture of your problem at the beginning.
Ok then your annulus will be very thin. Let's say, the outer radius from annulus will split the gap between solid and rectangle into 2 parts

Sorry, next time I'll post the picture. But all your replies is useful for me.
Now you are telling to split the geometry into two at the annulus region right??

If i split geometry in gambit , is it possible to combine the geometry in fluent??

no you create your second circle so that the gap between your solid-circle and rectangle-edge will be cutted in half

sorry can you pleas explain?

Now i just want to rotate the solid body (no sliding mesh) with this current geometry.

Next step I'll make sliding mesh.

no sliding mesh = no rotation
or you can use moving mesh or MRF (check points 10 and 11: http://aerojet.engr.ucdavis.edu/flue...g/main_pre.htm)

Attachment 16335

Attachment 16336

Thank you.. :-)

Do you have any simple tutorials for rotation or sliding meshing??

check on the web site I mentionned earlier, you can found the tutorials

I need meshing tutorial. The available tutorials are problems in Fluent solver. Any tutorial is available for meshing in gambit related to moving mesh/rotation?

i meshed the geometry in gambit. Initially I'm doing MRF ( by giving angular velocity to Circle keeping circle as wall). Can you check the meshing is correct? I split the faces and did meshing.

there is a tool for checking mesh quality in gambit:
http://aerojet.engr.ucdavis.edu/gamb....htm#gc_exmesh

Thank you.. Actually there will be no persons for helping. That why asking doubts like this. I'm new to all the cfd modelings. Now i got some idea about (theory) SRF,MRF,sliding mesh and dynamics mesh. Once again thank you.. :-)

Hi
I rotated circle inside the rectangle domain by giving circle as wall with a angular velocity. But I'm not getting required result. As you told earlier giving rotation to the annulus region (fluid) by considering concentric circle is also not possible because of less clearance between circle and rectangle. Is both the method obtain same result??

So can i consider a rectangular region around the circle and giving rotation to the region(shown in fig) between smaller rectangle and circle? Is it possible??

you need to set rotation speed on annulus domain, but no rotation to inner circle (solid), since it already belongs to the annulus domain (and consequently has rotation speed)
your last method won't work.
The easiest way would be to set only the inner circle with velocity (but without moving grid)

But the clearance is very less then how can i make annulus region and meshing it??