simulation on stirred vessels

Ray

HI! There,

Is there any one who had experience in simulating stirred vessels?

I encountered the following problems:

(1) how to create periodic boundary conditions?

(2) In 2d simulation, the residual can be reduced to 10-3 or even 10-4. But in 3d simulation, the fluent can only reduce the residual from 1.0 to 1.0E-1, and can not reduce it any more, though the rotating speed is still slow (say 5 -- 10 rpm).

I don't know what's wrong.

Could any one help me?

Ray