The objective of this paper is to investigate the modeling of transition in turbomachinery flows. Under steady state conditions four modes of transition can be identified. One of them, reverse transition, can be modeled sufficiently well by turbulence models. For the other modes — natural, bypass and separated-flow transition — specific models have to be applied. These transition models are either based on stability analysis or a statistic approach that describes the production and growth of turbulent spots in the intermittent flow.
This paper focuses on separated flow transition. Different models are presented and a classification is attempted. Based on these findings specific models are chosen and implemented into a Navier-Stokes solver to be studied in more detail. First an annular compressor cascade is computed two-dimensionally and the results are compared with experiments. In a second step three-dimensional computations are performed and the effect of transition modeling is analysed.