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ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

VELOCITY PROFILES IN THE TURBULENT FREE CONVECTION BOUNDARY LAYER

Get access (open in a dialog) DOI: 10.1615/IHTC6.3160
pages 193-197

Sinopsis

The turbulent free convection boundary layer along a vertical wall has been widely studied experimentally and theoretically. Still appreciable differences in the relations for the heat transfer coefficients and the velocity profile exist; the temperature profiles reported in literature agree better. We could show by calculating the heat transfer from a heat balance over the boundary layer using Cheesewright's temperature and velocity profiles that this is not consistent with his relation for the Nusselt number. We performed experiments in air with a 1.8 m length cooled vertical wall in a closed space. Temperature, velocity and turbulence profiles were measured at various heights in the turbulent part of the boundary layer. Our results indicated a good agreement with the turbulent temperature profile known from literature at Rax > 6.1· 109. The velocity profiles corresponded with the theoretically calculated velocities of Mason. They show clearly higher values for the maximum velocity than found by Cheesewright. We could show that for the Cheesewright study the heat balance over the boundary layer fits the Nu-relation if the higher velocities found by Mason are used.