Heat transfer with moderate free stream turbulence

Turbulence in turbine flows of gas turbine engines is generally inhomogeneous and is also characterized by wide ranges of intensity and scale. The interaction between Free Stream Turbulence (FST) and boundary layer turbulence (BLT) is complicated in all but the case of low values of both intensity and scale. In a recent investigation, an attempt was made to establish the effect of homogeneous FST on wall friction (when there is no heat transfer) in the relatively simple case of a flat plate, zero pressure gradient boundary layer. In the current paper, the method was extended for the prediction of heat transfer in the same flow field. In any problem involving heat and momentum transport, it is common to introduce some type of similarity between the two transport processes. The current method is based on the application of a similarity rule governing the spectra of turbulence intensity and temperature variance. The principal outcome is a method of establishing heat transfer in a given flow field for which experimental data are available under cold flow conditions and have been verified with the model prediction scheme.