About Mesh Interface options
 

Hi
I use Fluent recently. I am confused about the mesh interface options.
I often model the centrifugal pumps. When I create the interface, there are 5 interface options in ANSYS/Fluent v17.1. I don`t know the difference of these options. The options are Periodic Boundary Condition,Periodic Repeats,Coupled Wall,Matching,and mapped.
often I model the pumps,I chose none of them,and it seems to work fine.
Now anyone can help me ? anyone can explain the difference for me ?
Thanks!