The Profile Transformation (PT) method handles the pitch change across adjacent inter-row blade passages by scaling the flow profiles across the transient rotor stator (TRS) interface while imposing standard periodicity on the pitchwise periodic boundary. The scaling of the flow is proportional to the pitch ratio between the rotor and stator passages. The PT interface treatment is the same as the one described in Chapter 3. Therefore, PT TRS maintains full conservation and provides fast solutions to transient turbomachinery flow problems. The PT interface allows for transient interactions to take place between rotor and stator but, due to the pitch-wise approximation made on the periodic boundary, the dominant blade passing frequency on both the rotor and the stator is the rotor passing frequency.

The PT interface can be used to connect two passages with a large pitch difference. However, to obtain an accurate prediction of aerodynamic performance, the pitch ratio must be close to unity. This is possible by using multiple passages per row so that the ensemble pitch ratio is near unity.

For modeling information, see Profile Transformation in the CFX-Solver Modeling Guide.