The frame change interfaces model the interface between a rotating assembly and a stationary assembly. For details, see Frame Change/Mixing Model in the CFX-Solver Modeling Guide. When the analysis type is steady state, four options are available to model frame change:

For transient or Transient Blade Row simulations, the following four options are available to model frame change:

In addition, a frame change interface of type None is created for tip clearance regions and disconnected regions of mesh within a component (for example between an inlet section and a blade section). Periodic interfaces are used in regions where a portion of the flow field is repeated in many identical regions. The flow around a single turbine blade in a rotating machine, or around a single louvre in a whole array in a heat exchanger fin are such examples.