ISSN Online: 2377-424X
International Heat Transfer Conference 4
EXPERIMENTAL DETERMINATION OF THE TURBULENT PRANDTL NUMBER IN A DEVELOPING TEMPERATURE BOUNDARY LAYER
Resumo
Measurements of Prt were performed at five stations in a turbulent temperature boundary layer developing along a flat plate with a stepwise wall-temperature variation. The Prt values were calculated from the measured mean quantities as well as from the direct measurements of uv and vθ. The results agree reasonably well. A variation of Pr t across the boundary layer is found, clearly showing the invalidity of the usually assumed Reynolds analogy (Prt = 1).
For a developing temperature boundary layer it is impossible, except very close to the wall (y+ < 30), to indicate a universal Prt profile, which throws some doubt on the usefulness of Prt as a parameter to describe turbulent heat transfer.
For a developing temperature boundary layer it is impossible, except very close to the wall (y+ < 30), to indicate a universal Prt profile, which throws some doubt on the usefulness of Prt as a parameter to describe turbulent heat transfer.