Prediction of Transitional Heat Transfer Characteristics of Wake-Affected Boundary Layers

The presence of wake-passing in the gas turbine environment significantly modifies the heat transfer characteristics on the downstream blade surface by causing wake-induced transition. In this study, time-dependent boundary layer calculations were carried out using a model for wake-induced transition 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 over a flat plate. Comparison showed that the present time-dependent calculations yields more accurate results than existing steady superposition models.

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