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 GGI and MFR Theory. Therefore, PT TRS maintains full conservation and provides fast solutions to transient turbomachinery flow problems.
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 modeling multiple passages per row so that the ensemble pitch ratio is near unity.
The PT interface allows for transient interactions to take place between rotor and stator. The dominant blade passing frequency depends on the domain:
For the stator domain, the dominant frequency is equal to the rotor blade passing frequency.
For the rotor domain, the dominant frequency is equal to the rotor blade passing frequency multiplied by the number of passages modeled in the stator domain divided by the the number of passages modeled in the rotor domain.
For modeling information, see Profile Transformation in the CFX-Solver Modeling Guide.