Practical experience with the discrete Green's function approach to convective heat transfer

The heat transfer from a short uniform heat flux strip beneath a turbulent boundary layer with and without freestream turbulence was measured using a liquid crystal imaging technique. Freestream turbulence intensities were on the order of 12 percent. Data were taken at momentum thickness Reynolds nu mbers on the order of 1000 and 2000 for the turbulent and steady freestream s, respectively. Heat transfer enhancement due to the presence of freestrea m turbulence was quantified in terms of the ratio of the average St's on th e strip: turbulent freestream divided by steady freestream. Compared to the baseline case of a uniformly heated surface upstream of the strip, the hea t transfer enhancement decreased by 20 percent. The temperature distributio n measured on and downstream of the heated strip represented one column of a discrete Greens function that was used to predict the heat transfer for a rty arbitrarily specified thermal boundary condition, given the same flowfi eld. Predictions are compared against correlations and numerical prediction s as well as data from the literature. The details and practical applicatio ns of this approach to handling heat transfer with non-uniform thermal boun dary conditions are presented.