Each turbo component requires two instances of the passages that constitute a repeatable section. A GGI interface must be created to join the two instances. This domain interface will be selected as the sampling interface. A phase-shifted periodic domain interface connection is required on the outer periodic boundaries. This periodic interface is selected when defining the phase corrected interface. See Fourier Transformation Disturbance Settings in the CFX-Pre User's Guide for a description of the sampling domain interface.

For a given domain, optionally add one disturbance to the list of disturbances.

Those transient rotor stator interfaces not referenced by a disturbance will be treated with the Profile Transformation method.

All periodic and sampling interface pairs must use the Bitmap intersection method. The option that controls the intersection method is found in CFX-Pre in the details view for the domain interface, on the Basic Settings tab, under Mesh Connection Method > Mesh Connection > Intersection Control. For periodic and sampling interface pairs, the Bitmap method takes effect when the Intersection Control check box is cleared. When the Intersection Control check box is selected, the Option setting is set to Bitmap by default.

The Transient Rotor Stator interface must use the Direct intersection method. The option that controls the intersection method is found in CFX-Pre in the details view for the domain interface, on the Basic Settings tab, under Mesh Connection Method > Mesh Connection > Intersection Control. For a Transient Rotor Stator interface, the Direct method takes effect when the Intersection Control check box is cleared. If you select the Intersection Control check box, you must change the Option setting (from its default value of Bitmap) to Direct.

Ensure that no disturbance signal has a speed of zero relative to the component on which that signal acts.

When solving a simulation that involves the Fourier Transformation method (including the steady-state simulation for initialization), the use of double precision is strongly recommended for accuracy and robustness.

Some inlet boundaries might be required to have identical conditions, depending on the geometry. The same applies for outlet boundaries.

Consider a geometry as viewed in axial-radial space, with the axial coordinate measuring distance along the machine axis and the radial coordinate measuring distance from the machine axis. As viewed in this space, boundaries that overlap must have identical specified conditions. Boundaries that do not overlap, including those that only meet at a point, can have different specified conditions.

For example, consider the outlets in Figure 6.1: Example Fan Geometry as viewed in axial-radial space. Outlet A of passage 1 and outlet A of passage 2 overlap, so must have identical specified conditions. Similarly, outlet B of passage 1 and outlet B of passage 2 overlap, so must have identical specified conditions. Outlet A (of any passage) and outlet B (of any passage) do not overlap, so can have different specified conditions.

Figure 6.1: Example Fan Geometry