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1.
The previous work of Bachok et al. (Heat Mass Transf. 47:1643–1649, 2011) on the forced convection heat transfer on an isothermal moving surface in an external free stream is extended to the case when fluid injection through the surface, characterized by the parameter γ, is large. The asymptotic solution derived in this limit shows that the boundary layer has a double region structure, with an inviscid inner region of thickness O(γ) and an outer shear layer. Some further aspects of the original problem not treated in Bachok et al. (Heat Mass Transf. 47:1643–1649, 2011) are discussed as well as the analogous problem for a constant surface heat flux, where relatively small injection rates are seen to give rise to large increases in the surface temperature. 相似文献
2.
N.BACHOK A.ISHAK I.POP 《应用数学和力学(英文版)》2010,31(11):1421-1428
The unsteady viscous flow over a continuously permeable shrinking surface is studied. Similarity equations are obtained through the application of similar transformation techniques. Numerical techniques are used to solve the similarity equations for different values of the unsteadiness parameter, the mass suction parameter, the shrinking parameter and the Prandtl number on the velocity and temperature profiles as well as the skin friction coefficient and the Nusselt number. It is found that, different from an unsteady stretching sheet, dual solutions exist in a certain range of mass suction and unsteadiness parameters. 相似文献
3.
This paper presents both a numerical and analytical study in connection with the steady boundary layer flow and heat transfer
induced by a moving permeable semi-infinite flat plate in a parallel free stream. Both the velocities of the flat plate and
the free stream are proportional to x
1/3. The surface temperature is assumed to be constant. The governing partial differential equations are converted into ordinary
differential equations by a new similarity transformation. Numerical results for the flow and heat transfer characteristics
are obtained for various values of the moving parameter, transpiration parameter and the Prandtl number. Approximate analytical
solutions are also obtained when the suction or injection parameter is very large. It is found that dual solutions exist for
the case when the fluid and the plate move in the opposite directions. 相似文献
4.
The steady flow of an incompressible viscous fluid due to a rotating disk in a nanofluid is studied. The transformed boundary layer equations are solved numerically by a finite difference scheme, namely the Keller-box method. Numerical results for the flow and heat transfer characteristics are obtained for various values of the nanoparticle volume fraction parameter φ and suction/injection parameter h0. Two models for the effective thermal conductivity of the nanofluid, namely the Maxwell-Garnett model and the Patel model, are considered. It is found that for the Patel model, the heat transfer rate at the surface increases for both suction and injection, whereas different behaviors are observed for the Maxwell-Garnett model, i.e. increasing the values of φ leads to a decrease in the heat transfer rate at the surface for suction, but increases for injection. The results of this study can be used in the design of an effective cooling system for electronic components to help ensure effective and safe operational conditions. 相似文献
5.
The unsteady laminar flow of an incompressible micropolar fluid over a stretching sheet is investigated. The unsteadiness
in the flow and temperature fields is caused by the time-dependence of the stretching velocity and the surface temperature.
Effects of the unsteadiness parameter, material parameter and Prandtl number on the flow and heat transfer characteristics
are thoroughly examined. 相似文献
6.
An analysis is performed to study the heat transfer characteristics of steady two-dimensional boundary layer flow past a moving permeable flat plate in a nanofluid. The effects of uniform suction and injection on the flow field and heat transfer characteristics are numerically studied by using an implicit finite difference method. It is found that dual solutions exist when the plate and the free stream move in the opposite directions. The results indicate that suction delays the boundary layer separation, while injection accelerates it. 相似文献
7.
The steady laminar boundary layer flow and heat transfer from a warm, laminar liquid flow to a melting surface moving parallel
to a constant free stream is studied in this paper. The continuity, momentum and energy equations, which are coupled nonlinear
partial differential equations are reduced to a set of two nonlinear ordinary differential equations, before being solved
numerically using the Runge–Kutta–Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity
profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting
parameter, moving parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. It is
found that the problem admits dual solutions. 相似文献
8.
Radiation effects on the thermal boundary layer flow over a moving plate with convective boundary condition 总被引:2,自引:0,他引:2
The steady laminar boundary layer flow over a moving plate in a moving fluid with convective surface boundary condition and
in the presence of thermal radiation is investigated in this paper. Under certain conditions, the present problem reduces
to the classical Blasius and Sakiadis problems. The effects of radiation and convective parameters on the thermal field are
thoroughly examined and discussed. Dual solutions are found to exist when the plate and the fluid move in the opposite directions. 相似文献
9.
An analysis is carried out to study the steady two-dimensional stagnation-point flow and heat transfer from a warm, laminar liquid flow to a melting stretching/shrinking sheet. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, before being solved numerically using the Runge-Kutta-Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. 相似文献
10.
An analytical solution is presented for the boundary-layer flow and heat transfer over a permeable stretching/shrinking surface embedded in a porous medium using the Brinkman model. The problem is seen to be characterized by the Prandtl number $Pr$ , a mass flux parameter $s$ , with $s>0$ for suction, $s=0$ for an impermeable surface, and $s<0$ for blowing, a viscosity ratio parameter $M$ , the porous medium parameter $\Lambda $ and a wall velocity parameter $\lambda $ . The analytical solution identifies critical values which agree with those previously determined numerically (Bachok et al. Proceedings of the fifth International Conference on Applications of Porous Media, 2013) and shows that these critical values, and the consequent dual solutions, can arise only when there is suction through the wall, $s>0$ . 相似文献