Settings about domain interface
 

My domain interface：Fluid fluid，both were stationary fluid. shown on picture below,the "interface models" I chose was "General connection",but the "frame change/mixing model" should be set what? "none ","frozen rotor","stage","transient rotor stator"?and when should be these four types used for?

Where is your interface?

For a description of the differences have a look at the tutorials and read the documentation.