Prediction of transitional heat transfer characteristics of wake-affected boundary layers

The presence of wake-passing in the gas turbine environment significantly m odifies the heat transfer characteristics on the downstream blade surface b y causing wake-induced transition. In this study, time-dependent boundary l ayer calculations were carried out using a model for wake-induced transitio n based on a prescribed time-dependent intermittent function. The model is determined from the well-known turbulent spot propagation theory in a time- space diagram and from experimental evidence in the ensemble-averaged sense . Time-averaged heat transfer distributions are evaluated and compared with experimental results for different flow and wake-generating conditions ove r a flat plate. Comparison showed that the present time-dependent calculati ons yield more accurate results than existing steady superposition models.