Turbulent boundary layers were subjected to grid-generated free-stream turbulence to study the effects of length scale and intensity on heat transfer. Relative to conventional boundary layer thickness measures, test conditions included very small-scale free-stream turbulence. The boundary layers studied ranged from 400–2700 in momentum-thickness Reynolds number and from 450–1900 in enthalpy-thickness Reynolds number. Free-stream turbulence intensities varied from 0.1–8.0%. Ratios of free-stream length scale to boundary-layer momentum thickness ranged from 4.4–32.5. The turbulent-to-viscous length-scale ratios presented are the smallest found in the heat-transfer literature; the ratios spanned from 115–1020. The turbulent-to-thermal ratios (using enthalpy thickness as the thermal scale) are also the smallest reported; the ratios ranged from 3.2–12.3. Relative to clean-free-stream expectations based on the momentum- and enthalpy-thickness Reynolds numbers, the skin friction coefficient increased by up to 16%, and the Stanton number increased by up to 46%.
Heat Transfer in Turbulent Boundary Layers Subjected to Free-Stream Turbulence—Part I: Experimental Results
Contributed by the International Gas Turbine Institute and presented at the National Heat Transfer Conference, Albuquerque, New Mexico, August 14–17, 1999, of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS. Manuscript received by the IGTI, October 29, 2002. Associate Editor: R. Bunker.
Barrett, M. J., and Hollingsworth, D. K. (April 23, 2003). "Heat Transfer in Turbulent Boundary Layers Subjected to Free-Stream Turbulence—Part I: Experimental Results ." ASME. J. Turbomach. April 2003; 125(2): 232–241. https://doi.org/10.1115/1.1538622
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