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2012年 第33卷 第8期    刊出日期：2012-08-10

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论文

Flow of micropolar fluid between two orthogonally moving porous disks

司新辉;郑连存;张欣欣;司新毅

2012, 33(8):  963-974.  doi:10.1007/s10483-012-1598-8

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The unsteady, laminar, incompressible, and two-dimensional flow of a micropolar fluid between two orthogonally moving porous coaxial disks is considered. The extension of von Karman’s similarity transformations is used to reduce the governing partial differential equations (PDEs) to a set of non-linear coupled ordinary differential equations (ODEs) in the dimensionless form. The analytical solutions are obtained by employing the homotopy analysis method (HAM). The effects of various physical parameters such as the expansion ratio and the permeability Reynolds number on the velocity fields are discussed in detail.

MHD flow of upper-convected Maxwell fluid over porous stretching sheet using successive Taylor series linearization method

S. S. MOTSA;T. HAYAT;O. M. ALDOSSARY

2012, 33(8):  975-990.  doi:10.1007/s10483-012-1599-x

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This paper investigates the magnetohydrodynamic (MHD) boundary layer flow of an incompressible upper-convected Maxwell (UCM) fluid over a porous stretching surface. Similarity transformations are used to reduce the governing partial differential equations into a kind of nonlinear ordinary differential equations. The nonlinear prob- lem is solved by using the successive Taylor series linearization method (STSLM). The computations for velocity components are carried out for the emerging parameters. The numerical values of the skin friction coefficient are presented and analyzed for various parameters of interest in the problem.

Calculation of cell face velocity of non-staggered grid system

李旺;宇波;王欣然;孙树瑜

2012, 33(8):  991-1000.  doi:10.1007/s10483-012-1600-6

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In this paper, the cell face velocities in the discretization of the continu- ity equation, the momentum equation, and the scalar equation of a non-staggered grid system are calculated and discussed. Both the momentum interpolation and the linear interpolation are adopted to evaluate the coefficients in the discretized momentum and scalar equations. Their performances are compared. When the linear interpolation is used to calculate the coefficients, the mass residual term in the coefficients must be dropped to maintain the accuracy and convergence rate of the solution.

Effect of viscous dissipation and heat source on flow and heat transfer of dusty fluid over unsteady stretching sheet

B. J. GIREESHA;G. S. ROOPA;C. S. BAGEWADI

2012, 33(8):  1001-1014.  doi:10.1007/s10483-012-1601-9

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This paper investigates the problem of hydrodynamic boundary layer flow and heat transfer of a dusty fluid over an unsteady stretching surface. The study considers the effects of frictional heating (viscous dissipation) and internal heat generation or ab- sorption. The basic equations governing the flow and heat transfer are reduced to a set of non-linear ordinary differential equations by applying suitable similarity transformations. The transformed equations are numerically solved by the Runge-Kutta-Fehlberg-45 order method. An analysis is carried out for two different cases of heating processes, namely, variable wall temperature (VWT) and variable heat flux (VHF). The effects of various physical parameters such as the magnetic parameter, the fluid-particle interaction pa- rameter, the unsteady parameter, the Prandtl number, the Eckert number, the number density of dust particles, and the heat source/sink parameter on velocity and temperature profiles are shown in several plots. The effects of the wall temperature gradient function and the wall temperature function are tabulated and discussed.

Mixed convection flow in vertical channel with boundary conditions of third kind in presence of heat source/sink

J. C. UMAVATHI;J. PRATHAP KUMAR;JAWERIYA SULTANA

2012, 33(8):  1015-1034.  doi:10.1007/s10483-012-1602-8

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The effects of viscous dissipation and heat source/sink on fully developed mixed convection for the laminar flow in a parallel-plate vertical channel are investigated. The plate exchanges heat with an external fluid. Both conditions of equal and different reference temperatures of the external fluid are considered. First, the simple cases of the negligible Brinkman number or the negligible Grashof number are solved analytically. Then, the combined effects of buoyancy forces and viscous dissipation in the presence of heat source/sink are analyzed by a perturbation series method valid for small values of the perturbation parameter. To relax the conditions on the perturbation parameter, the velocity and temperature fields are solved by using the Runge-Kutta fourth-order method with the shooting technique. The velocity, temperature, skin friction, and Nusselt numbers at the plates are discussed numerically and presented through graphs.

Slip and induced magnetic field effects on peristaltic transport of Johnson-Segalman fluid

T. HAYAT;S. NOREEN;A. ALSAEDI

2012, 33(8):  1035-1048.  doi:10.1007/s10483-012-1603-6

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The peristaltic flow of a Johnson-Segalman fluid in a planar channel is investigated in an induced magnetic field with the slip condition. The symmetric nature of the flow in a channel is utilized. The velocity slip condition in terms of shear stresses is considered. The mathematical formulation is presented, and the equations are solved under long wavelength and low Reynolds number approximations. The perturbation solutions are established for the pressure, the axial velocity, the micro-rotation component, the stream function, the magnetic-force function, the axial induced magnetic field, and the current distribution across the channel. The solution expressions for small Weissenberg numbers are derived. The flow quantities of interest are sketched and analyzed.

Equilibrium equations for 3D critical buckling of helical springs

武秀根;郑百林;贺鹏飞;刘曙光

2012, 33(8):  1049-1058.  doi:10.1007/s10483-012-1604-x

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In most cases, the research on the buckling of a helical spring is based on the column, the spring is equivalent to the column, and the torsion around the axial line is ignored. A three-dimensional (3D) helical spring model is considered in this paper. The equilibrium equations are established by introducing two coordinate systems, the Frenet and the principal axis coordinate systems, to describe the spatial deformation of the center line and the torsion of the cross section of the spring, respectively. By using a small deformation assumption, the variables of the deflection can be expanded into Taylor’s series, and the terms of high orders are ignored. Hence, the equations can be simplified to the functions of the twist angle and the arc length, which can be solved by a numerical method. The reaction loads of the spring caused by the axial load subjected to the center point are also discussed, giving the boundary conditions for the solution to the equilibrium equations. The present work is useful to the research on the behavior of the post-buckling of the compressed helical spring.

Thermal stresses in infinite circular cylinder subjected to rotation

A. M. ABD-ALLA;G. A. YAHYA

2012, 33(8):  1059-1078.  doi:10.1007/s10483-012-1605-7

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The present investigation is concerned with the effect of rotation on an infi- nite circular cylinder subjected to certain boundary conditions. An analytical procedure for evaluation of thermal stresses, displacements, and temperature in rotating cylinder subjected to thermal load along the radius is presented. The dynamic thermal stresses in an infinite elastic cylinder of radius a due to a constant temperature applied to a variable portion of the curved surface while the rest of surface is maintained at zero temperature are discussed. Such situation can arise due to melting of insulating material deposited on the surface cylinder. A solution and numerical results are obtained for the stress components, displacement components, and temperature. The results obtained from the present semi-analytical method are in good agreement with those obtained by using the previously developed methods.

Equations of Langmuir turbulence and Zakharov equations: smoothness and approximation

游淑军;郭柏灵;宁效琦

2012, 33(8):  1079-1092.  doi:10.1007/s10483-012-1606-9

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A family of systems parameterized by H > 0, which describes the Langmuir turbulence, is considered. The asymptotic behavior of the solutions (E^H, n^H) when H goes to zero is studied. The results of convergence of (E^H, n^H) to the couple (E, n) which is the solution to the Zakharov equations are stated.

Comments on “General solutions of plane problem for power function curved cracks”

陈宜周

2012, 33(8):  1093-1094.  doi:10.1007/s10483-012-1607-7

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