Buoyancy Effects on Heat and Mass Transfer in Boundary Layers Adjacent to Inclined, Continuous, Moving Sheets


The combined buoyancy effects of thermal and mass diffusion on the heat and mass transfer characteristics of a laminar boundary layer adjacent to a continuous plate moving in a vertical or inclined direction through a quiescent ambient fluid are studied analytically. The surface of the plate is either maintained at a uniform temperature/concentration or subjected to a uniform surface heat/mass flux. The governing equations describing the nonsimilar boundary layers are reduced to a dimensionless form and then solved by a finite-difference method. Numerical results for the local friction factor and the local and average Nusselt/Sherwood numbers are presented for a Prandtl number of 0.7 with Schmidt numbers of 0.6 and 2.0. It is found that for the thermal buoyancy assisting condition, the wall shear stress and the surface heat/mass transfer rates are further increased when the buoyancy force from mass diffusion assists the thermal buoyancy force, but are reduced when the two buoyancy forces oppose each other. These trends are reversed for the thermally opposing condition. In addition, the effects of the buoyancy forces are found to decrease as the angle of inclination from the vertical increases. Finally, comparisons of results are made between the two surface heating/diffusing conditions and between the moving and stationary plates.


Mechanical and Aerospace Engineering

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Article - Journal

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© 1980 Taylor & Francis, All rights reserved.

Publication Date

01 Jan 1980