On the viscous dissipation in the boundary layer of a high Prandtl number fluid in laminar flow over a flat plate

1985 ◽  
Vol 36 (4) ◽  
pp. 624-628 ◽  
Author(s):  
Seppo A. Korpela
Keyword(s):  
Boundary Layer ◽  
Laminar Flow ◽  
Prandtl Number ◽  
Flat Plate ◽  
Viscous Dissipation ◽  
High Prandtl Number

Heat Transfer in the Laminar Boundary Layer Over an Impulsively Started Flat Plate

1975 ◽  
Vol 97 (3) ◽  
pp. 482-484 ◽  
Author(s):  
C. B. Watkins
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Laminar Flow ◽  
Flat Plate ◽  
Constant Temperature ◽  
Laminar Boundary Layer ◽  
Temperature Difference ◽  
Thermal Boundary Layer ◽  
Numerical Solutions ◽  
Prandtl Numbers

Numerical solutions are described for the unsteady thermal boundary layer in incompressible laminar flow over a semi-infinite flat plate set impulsively into motion, with the simultaneous imposition of a constant temperature difference between the plate and the fluid. Results are presented for several Prandtl numbers.

Mass transfer in laminar flow

1954 ◽  
Vol 221 (1144) ◽  
pp. 78-99 ◽  
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Natural Convection ◽  
Laminar Flow ◽  
Flat Plate ◽  
The Body ◽  
Liquid Fuels ◽  
Fluid Stream ◽  
Mean Values ◽  
Fluid Properties

Starting from the differential equation of mass transfer in laminar flow and the appropriate boundary condition, expressions are derived for the rate of mass transfer from ( a ) a flat plate in a longitudinal fluid stream, ( b ) a vertical flat plate by natural convection, ( c ) the forward stagnation point of a sphere in a fluid stream. Only outward mass transfer is considered; this corresponds to blowing outwards from the plate at a rate inversely proportional to the boundary-layer thickness. The Kármán-Pohlhausen-Kroujiline method is used. Where appropriate the Prandtl or Schmidt number has been taken as 0⋅71. The calculations are valid for all mass-transfer processes for which a single diffusion coefficient can be ascribed to the diffusing property, but are particularly relevant to the combustion of liquid fuels, for which the outward mass-transfer rates are so high that important deviations occur from boundary-layer profiles without mass transfer. Despite the great temperature variations present in boundary layers with combustion, mean values for the fluid properties are assumed. In the case of natural convection, it is assumed that the body forces on the fluid in the boundary layer are everywhere zero; this leads to a less serious over-estimate of the buoyancy than the usual assumptions which are valid only for small temperature differences.

The heated laminar vertical jet

1967 ◽  
Vol 29 (2) ◽  
pp. 305-315 ◽  
Author(s):  
R. S. Brand ◽  
F. J. Lahey
Keyword(s):  
Boundary Layer ◽  
Temperature Distribution ◽  
Laminar Flow ◽  
Prandtl Number ◽  
Exact Solutions ◽  
Two Dimensional ◽  
Boundary Layer Equations ◽  
Prandtl Numbers ◽  
Vertical Jet ◽  
Steady Laminar

The boundary-layer equations for the steady laminar flow of a vertical jet, including a buoyancy term caused by temperature differences, are solved by similarity methods. Two-dimensional and axisymmetric jets are treated. Exact solutions in closed form are found for certain values of the Prandtl number, and the velocity and temperature distribution for other Prandtl numbers are found by numerical integration.

Wall Temperature and Prandtl Number Effects on Turbulent Boundary Layer Thicknesses and Shape Factors for Subsonic Compressible Gas Flow Over a Flat Plate

1969 ◽  
Author(s):  
W. J. Kelnhofer
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Prandtl Number ◽  
Flat Plate ◽  
Wall Temperature ◽  
Gas Flow ◽  
Density Variation ◽  
Shape Factors ◽  
Heating And Cooling ◽  
Subsonic Gas Flow

Based on n-power velocity and temperature profiles a method of computing various turbulent boundary layer thicknesses and shape factors affected by wall temperature and Prandtl number for fully developed subsonic gas flow over a flat plate is presented. Density variation in the boundary layer is given main consideration. Numerical computations include both heating and cooling of gas. Boundary layer thicknesses and shape factors are shown to be significantly affected by wall temperature and to a lesser degree by Prandtl number. An experiment is described which involved air flow up to 30 m/sec over a flat plate maintained at constant wall temperatures up to 250 C. Comparisons between theory and experiment are good.

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