ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
HEAT TRANSFER IN A TURBULENT BOUNDARY LAYER BEHIND A TWO-DIMENSIONAL BLUFF BODY AT DIFFERENT Pr NUMBERS
Resumo
Measurements downstream of an obstacle in fluids of different Pr suggest that maximum disturbances in the sublayer do not coincide with maximum turbulence
in the shear layer along the reattachment
region. Unlike the case of Pr = 1, for
higher obstacles and Pr >> l, an upstream
shift of the maximum heat transfer is observed.
The length of the separation region
l reflects the intensity of reattachment.
With a reference to this, Nul ~
Rel·R0−0.2 for Pr = 1. In the region of redevelopment, there exist two distinct stages of return to the ordinary heat transfer, with a significant effect of the turbulence memory. In the first stage of relaxation L = 0.4x. A neglect of the memory effect leads to overestimated values of the turbulent Prandtl number.