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Showing papers by "Ephraim M Sparrow published in 1966"


Journal ArticleDOI
TL;DR: In this article, a wide-ranging analytical investigation of laminar film condensation is presented, which includes interfacial resistance, superheating, free convection due to both temperature and concentration gradients, mass diffusion and thermal diffusion, and variable properties in both the liquid and the gas-vapor regions.

384 citations


Journal ArticleDOI
TL;DR: In this article, the authors measured the directional distribution of light reflected from roughened surfaces with measurements made of plane-polarized components of reflected light as well as of mixed radiation.
Abstract: Directional distribution of light reflected from roughened surfaces with measurements made of plane-polarized components of reflected light as well as of mixed radiation

157 citations


Journal ArticleDOI
TL;DR: In this article, a wide-ranging experimental study aimed at determining both the details of the flow field and the pressure drop and friction factor characteristics for turbulent flow in eccentric annular ducts was performed.
Abstract: The investigation to be described here is a wide-ranging experimental study aimed at determining both the details of the flow field and the pressure drop and friction factor characteristics for turbulent flow in eccentric annular ducts. The experiments were performed utilizing three annular ducts of different diameter ratios; in each case the eccentricity was varied from zero (concentric annulus) to unity (walls in contact). To provide the broadest possible perspective, the measurements of the velocity field are presented in three different ways. First, contour maps showing lines of constant velocity are constructed. From these are deduced circumferential distributions of the local shear stress on the bounding walls. Velocity profiles along lines normal to the walls are represented in terms of both law-of-the-wall variables and defect-law variables. Neither of these representations affords complete agreement with the universal circular-tube distributions. In general, the defect law provides a somewhat closer correlation of the results for the eccentric annulus with those for the tube. The experimental findings do not substantiate a prior analytical model which assumes that the universal law of the wall applies on all lines normal to the bounding walls of the annulus. Friction factors, based on static pressure measurements, are shown to decrease with increasing eccentricity. The measured friction factors are in fair agreement with those of analysis. Hydrodynamic development lengths, deduced from entrance-region pressure data, are found to increase with increasing eccentricity. Circumferential pressure variations also increase with eccentricity.

61 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of asymmetric heating on fully developed turbulent heat transfer has been carried out in a rectangular duct of aspect ratio 5:1, where the two long sides of the rectangular cross section could be heated at different preselected rates, while the two short sides were unheated.
Abstract: An experimental investigation of the effect of asymmetrical heating on fully developed turbulent heat transfer has been carried out. The test apparatus was a rectangular duct of aspect ratio 5:1. The duct was constructed so that the two long sides of the rectangular cross section could be heated at different preselected rates, while the two short sides were unheated. Two cases of asymmetrical heating were studied: (a) One of the two long sides was heated, while the second was unheated; (b) both of the long sides were heated, with the heating rate at one side being twice that of the other. For the first case, the heat transfer coefficients are lower than those for the symmetrically heated duct. For the second case, the coefficients for the more strongly heated wall are also below the values for symmetrical heating, while the coefficients for the lesser-heated wall are greater than the symmetric heating results. These findings are in qualitative agreement with analytical predictions for the parallel-plate channel. Furthermore, by applying an analytically motivated correlation procedure (reference [10]), it was shown that overall Nusselt number results for asymmetric heating could be brought into virtual coincidence with those for symmetric heating.

51 citations





Journal ArticleDOI
TL;DR: In this paper, the thermal boundary condition represents a balance between the convective heat transfer from the boundary layer into the wall and the enthalpy rise of the coolant gas as it passes through the porous wall.

7 citations


Journal ArticleDOI
TL;DR: In this article, the hydrodynamic stability of the laminar boundary layer on a continuous moving surface is analyzed within the framework of small-perturbation stability theory, and a complete stability diagram is mapped out.
Abstract: The characteristics of the laminar boundary layer on a continuous moving surface are described and an experiment is performed to demonstrate that such a flow is physically realizable. The hydrodynamic stability of the flow is analysed within the framework of small-perturbation stability theory. A complete stability diagram is mapped out. The critical Reynolds number is found to be substantially higher than that for the Blasius flow and, correspondingly, the critical layer lies closer to the wall. The disturbance amplitude function and its derivative are numerically evaluated, from which are derived the vector flow field of the disturbance, the resultant flow field (main flow plus disturbances), the root-mean-square distributions of the disturbance velocity components, and the distributions of the kinetic energy and the Reynolds stress. The energy criterion for stability is also investigated and is found to be consistent with the solutions of the eigenvalue problem.

7 citations


Journal ArticleDOI
TL;DR: In this paper, an experimental investigation of free convection in an air-water vapor boundary layer at the stagnation point of a horizontal cylinder is presented. But the results of both experiment and analysis indicate that the heat transfer decreases as the surface mass-transfer rate increases.

2 citations