Steady nonsimilar axisymmetric water boundary layers with variable viscosity and Prandtl number
TL;DR: In this article, the influence of temperature-dependent viscosity and Prandtl number on the steady nonsimilar laminar forced convection flow over a rotating sphere up to the point of separation was analyzed.
Abstract: An analysis is performed to study the influence of temperature-dependent viscosity and Prandtl number on the steady nonsimilar laminar forced convection flow over a rotating sphere up to the point of separation. The difficulties arising at the starting point of the streamwise coordinate and at the point of separation are overcome by applying the method of quasilinear implicit finite difference scheme with an appropriate selection of finer step size along the streamwise direction. The results indicate that the effect of variable viscosity and Prandtl number is to move the point of separation downstream, but the rotation parameter has the reverse effect. For higher wall temperature than the free stream temperature, beyond a certain critical value of the dissipation parameter, the cooler free stream is unable to cool the hot wall due to the “heat cushion” provided by the frictional heating. The heat transfer rate is found to depend strongly on viscous dissipation but the skin frictions are little affected by it. In general, the results pertaining to variable fluid properties differ significantly from those of constant fluid properties.
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TL;DR: In this article, the influence of non-uniform slot injection (suction) into steady axi-symmetric laminar incompressible boundary layer flows with temperature dependent viscosity and Prandtl number has been examined from the origin of the streamwise coordinate to the exact point of separation.
Abstract: The influence of non-uniform slot injection (suction) into steady axi-symmetric laminar incompressible boundary layer flows with temperature dependent viscosity and Prandtl number has been examined from the origin of the streamwise coordinate to the exact point of separation. The difficulties in obtaining the non-similar solutions at the origin of the streamwise coordinate, at the edges of the slot and at the point of separation have been overcome by applying an implicit finite difference scheme with the quasilinearization technique and an appropriate selection of finer step size along the streamwise coordinate. The results indicate that the separation can be delayed by non-uniform slot suction and also by moving the slot downstream but the effect of non-uniform slot injection is just the opposite. Further, the effect of variable fluid properties is to move the point of separation downstream but rotation parameter has the reverse effect.
49 citations
TL;DR: In this paper, the authors present an analytical/numerical method and modelling/simulation techniques for contact conduction/contact resistance. But they do not consider the non-Fourier effects and laser/pulse heating in complex geometries, composites/layered media and fins.
Abstract: 0017doi:1 * C E 2.1. Contact conduction/contact resistance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 824 2.2. Microscale/nanoscale heat transport, non-Fourier effects and laser/pulse heating . . . . . . . . . . . . . . 824 2.3. Heat conduction in complex geometries, composites/layered media and fins . . . . . . . . . . . . . . . . . . 825 2.4. Analytical/numerical methods and modelling/simulation techniques . . . . . . . . . . . . . . . . . . . . . . . . 825 2.5. Experimental studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 825 2.6. Thermal stresses and thermomechanical problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 825 2.7. Miscellaneous applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 825
35 citations
Cites background from "Steady nonsimilar axisymmetric wate..."
...Temperature dependent viscosity effects on convection up to the transition point on a spinning sphere produced a marked effect on heat transfer coefficients [688]....
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...[688] P....
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TL;DR: In this article, the non-uniform slot injection (suction) into water boundary layer flow over a yawed infinite circular cylinder is analyzed including the temperature-dependent viscosity and Prandtl number.
Abstract: The non-uniform slot injection (suction) into water boundary layer flow over a yawed infinite circular cylinder is analyzed including the temperature-dependent viscosity and Prandtl number. The difficulties arising at the starting point of the streamwise coordinate, at the edges of the slot and at the point of separation are overcome by applying the implicit finite difference scheme in combination with the quasilinearization technique. The results indicate that the separation can be delayed by non-uniform slot suction and also by moving the slot downstream but effect of non-uniform slot injection is just the opposite. Further, the effect of variable fluid properties is to move the point of separation downstream but yaw angle has very little affect on the location of the point of separation.
31 citations
TL;DR: In this paper, the thermal conductivity and permeability of tree-like branching networks are analyzed and compared with that created by heat conduction in terms of thermal transfer and flow of working fluid.
Abstract: To design an ideal tree-like branching networks with good performance on both heat transfer and flow of working fluid, the thermal conductivity and permeability of the tree-like branching networks are calculated. In addition, the thermal conductivity created by heat convection is analyzed and compared with that created by heat conduction. It’s found that when the temperature difference between wall and fluid in each branching level is treated as different, heat convection accounts for larger proportion than heat conduction in heat transfer. Furthermore, the difference of each branching level’s temperature difference between wall and fluid plays a key role in heat transfer. There exists large error in calculation of heat transfer, if the difference of each branching level’s temperature difference between wall is not considered.
21 citations
TL;DR: In this paper, the authors examined the unsteady magnetohydrodynamic (MHD) mixed convection flow over a sphere combined with variable fluid properties, and found that vanishing skin friction is prevented or at least delayed by enhancing the mixed convections in both the cases of steady and unstrainy fluid flow.
Abstract: This paper examines the unsteady magnetohydrodynamic (MHD) mixed convection flow over a sphere combined with variable fluid properties. An implicit finite difference scheme, together with the quasi-linearization, is used to find non-similar solutions for the governing equations. The vanishing skin friction is prevented or at least delayed by enhancing the mixed convection in both the cases of steady and unsteady fluid flow. Both skin friction and heat transfer coefficients are found to be increasing with an increase in time or MHD parameter.
13 citations
References
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Book•
01 Jan 1973TL;DR: CRC handbook of chemistry and physics, CRC Handbook of Chemistry and Physics, CRC handbook as discussed by the authors, CRC Handbook for Chemistry and Physiology, CRC Handbook for Physics,
Abstract: CRC handbook of chemistry and physics , CRC handbook of chemistry and physics , کتابخانه مرکزی دانشگاه علوم پزشکی تهران
52,268 citations
Book•
01 Jan 1955
TL;DR: The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part, denoted as turbulence as discussed by the authors, and the actual flow is very different from that of the Poiseuille flow.
Abstract: The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path. Because of viscosity, the velocity of the particles near the wall is smaller than that of the particles at the center. i% order to maintain the motion, a pressure decrease is required which, for laminar flow, is proportional to the first power of the mean flow velocity. Actually, however, one ob~erves that, for larger Reynolds numbers, the pressure drop increases almost with the square of the velocity and is very much larger then that given by the Hagen Poiseuille law. One may conclude that the actual flow is very different from that of the Poiseuille flow.
17,321 citations
"Steady nonsimilar axisymmetric wate..." refers background in this paper
...However, since the variations of thermal conductivity (k) and viscosity (#) [and hence Prandtl number (Pr)] with temperature are quite significant, the viscosity and Prandtl number are assumed to vary as an inverse linear function of temperature (T) [ 14], [21 ]: 1 1 #=bl+b2T and P r - - - , (1) Cl + c2T where b l = 53....
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...It has long been recognized that the stability of a laminar boundary layer is markedly affected by the heat transfer and, in at least some cases, this phenomenon arises from the change in curvature of the velocity and temperature profiles due to the variation of temperature-dependent fluid properties [14]....
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...A similar trend has been observed in the case of constant fluid properties for parallel flow past a flat plate at zero incidence [14] and also for incompressible boundary layer flow over a rotating sphere [9]....
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5,562 citations
Book•
30 Nov 1961
TL;DR: In this article, the authors propose Matrix Methods for Parabolic Partial Differential Equations (PPDE) and estimate of Acceleration Parameters, and derive the solution of Elliptic Difference Equations.
Abstract: Matrix Properties and Concepts.- Nonnegative Matrices.- Basic Iterative Methods and Comparison Theorems.- Successive Overrelaxation Iterative Methods.- Semi-Iterative Methods.- Derivation and Solution of Elliptic Difference Equations.- Alternating-Direction Implicit Iterative Methods.- Matrix Methods for Parabolic Partial Differential Equations.- Estimation of Acceleration Parameters.
5,317 citations
TL;DR: In this paper, the influence of variable viscosity on laminar boundary layer flow and heat transfer due to a continuously moving flat plate is examined by means of similarity solutions and deviation of the velocity and temperature fields.
Abstract: The influence of variable viscosity on laminar boundary layer flow and heat transfer due to a continuously moving flat plate is examined. The fluid viscosity is assumed to vary as an inverse linear function of temperature. By means of the similarity solutions and deviation of the velocity and temperature fields as well as of the skin friction and heat transfer results from their constant values are determined.
159 citations
"Steady nonsimilar axisymmetric wate..." refers background in this paper
...However, since the variations of thermal conductivity (k) and viscosity (#) [and hence Prandtl number (Pr)] with temperature are quite significant, the viscosity and Prandtl number are assumed to vary as an inverse linear function of temperature (T) [ 14], [21 ]: 1 1 #=bl+b2T and P r - - - , (1) Cl + c2T where b l = 53....
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