Simulation of stirred tank using sliding mesh technique
 

I have a moderate experience in gambit & fluent.
but I face a problem when I carry out the geometry of the stirred tank by gambit & export it to fluent,the fluent perform two undefined walls.
Could any one answer me why this walls is performed.
I attached the gambit (msh) & fluent file in this link:-
http://www.zshare.net/download/99196312ab359d5f/