Evaluation of algebraic transition models for application to unsteady flows in low-pressure turbines

Currently, numerical simulation models for design of low-pressure turbines need submodels for determining the onset and path of transition. It is well known that such models must include the effects of passing wakes. In this paper, data taken in an experiment that simulates flow over the suction surface of a low-pressure turbine blade, as affected by passing wakes, are used for testing models from the literature. The base case data set replicates reasonable design conditions. A second case with double the wake spacing of the base case is applied to heighten the effects of between-wake calming. A third case with high background freestream turbulence intensity allows testing models for application to high disturbance level flows. Tested are (1) separated flow transition onset models such as those of Mayle and of Davis et al. and (2) attached flow transition onset models, such as those of Mayle, Abu-Ghannam and Shaw, Suzen and Huang and Drela. The dependent variables of the models, time-resolved locations of transition onset, are compared to time-resolved experimental values for transition onset. The transition onset values from the models are computed by assuming that the correlations can be applied in a quasistatic way using instantaneous values of the input parameters computed from the experimental data. Comparisons of the three cases are made to discuss the robustness of the transition onset models. Previously, the base case was presented. New in this paper are (1) modeling of an increased wake spacing data set, (2) modeling of a data set with a highly turbulent approach flow and (3) the comparison of the two with the base case results.