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Study of diffusion from a line source in a turbulent boundary layer: preliminary, subject to revision

Date

1962-10

Authors

Poreh, Michael, author
Cermak, J. E. (Jack E.), author
Colorado State University, publisher

Journal Title

Journal ISSN

Volume Title

Abstract

Diffusion of a scalar quantity (ammonia gas) from a steady line source within a two-dimensional turbulent boundary layer is studied. Using a long 6 x 6 ft square test section, the boundary-layer thickness varied from 5 to 11 in. for distances of 3 to 43.5 ft downstream with air speeds from 9 to 16 ft/sec. Measurements of mean ammonia concentrations in air are reported, analyzed and compared with a few measurements of heat transfer in similar conditions. Formulation of the results takes into consideration the transverse non homogeneity of the velocity field and also divides the downstream diffusion field into four zones. Measurements of the mean velocity field and the mean concentration field permit the flux of mass in the vertical direction to be calculated through the equation of mass conservation. The use of an eddy diffusivity coefficient to describe the processes of turbulent diffusion is discussed and it is shown that for a long distance downstream of the source, such a coefficient cannot be related to the local Eulerian variables of the boundary-layer flow.

Description

CER62JEC-MP63.
October 1962.
Includes bibliographical references.

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Subject

Turbulent boundary layer
Turbulence
Fluid dynamics

Citation

Associated Publications