Nonsimilar mixed convection flow of a non-Newtonian fluid past a vertical wedge

Summary The flow and heat transfer characteristics of a second-order fluid over a vertical wedge with buoyancy forces have been analysed. The coupled nonlinear partial differential equations governing the nonsimilar mixed convection flow have been solved numerically using Keller box method. The effects of the buoyancy parameter, viscoelastic parameter, mass transfer parameter, pressure gradient parameter, Prandtl number and viscous dissipation parameter on the skin friction and heat transfer have been examined in detail. Particular cases of the present results match exactly with those available in the literature.     

Slow flow of a non-Newtonian liquid past a fluid sphere

Summary The motion of a non-Newtonian fluid past a Newtonian fluid sphere has been investigated using the Stokes approximation. The stream functions characterizing the internal and external flow fields have been determined and the special case of flow past a solid sphere is deduced. The drag experienced by the fluid sphere has been evaluated and found to be greater than the classical counterpart.     

Flow of micropolar fluid past a continuously moving plate

A similarity analysis of the flow and heat transfer past a continuously moving semi-infinite plate in a micropolar fluid is presented. The velocity, micro-rotation distribution and the temperature profiles are shown on graphs and the numerical values of the skin friction and the rate of heat transfer are entered in tables. The effects of $\text{K}$ (coupling parameter) and $\text{G}$ (micro-rotation parameter) are discussed.     

MHD boundary-layer flow of a micropolar fluid past a wedge with variable wall temperature

Summary The steady laminar MHD boundary-layer flow past a wedge immersed in an incompressible micropolar fluid in the presence of a variable magnetic field is investigated. The governing partial differential equations are transformed to the ordinary differential equations using similarity variables, and then solved numerically using a finite-difference scheme known as the Keller-box method. Numerical results show that the micropolar fluids display drag reduction and consequently reduce the heat transfer rate at the surface, compared to the Newtonian fluids. The opposite trends are observed for the effects of the magnetic field on the fluid flow and heat transfer characteristics.     

Analytical solutions of hydromagnetic boundary-layer flow of a non-Newtonian power-law fluid past a continuously moving surface

Summary The boundary-layer flow of a power-law non–Newtonian fluid over a continuously moving surface in the presence of a magnetic field B(x) applied perpendicular to the surface has been investigated. An analytical solution is obtained and compared with the numerical solution of the resulting non linear ordinary differential equation. The effects of the Stewart number (N) and the power law-index (n) on the velocity profiles and the skin-friction are studied.     

Thermal boundary layer flow of a micropolar fluid past a wedge with constant wall temperature

Summary The steady laminar flow of micropolar fluids past a wedge has been examined with constant surface temperature. The similarity variables found by Falkner and Skan are employed to reduce the streamwise-dependence in the coupled nonlinear boundary layer equation. Numerical solutions are presented for the heat transfer characteristics with Pr=1 using the fourth-order Runge-Kutta method, and their dependence on the material parameters is discussed. The distributions of dimensionless temperature and Nusselt number across the boundary layer are compared with the corresponding flow problems for a Newtonian fluid over wedges. Numerical results show that for a constant wedge angle with a given Prandtl number Pr=1, the effect of increasing values ofK results in an increasing thermal boundary thickness for a micropolar fluid, as compared with a Newtonian fluid. For the case of the constant material parameterK, however, the heat transfer rate for a micropolar fluid is lower than that of a Newtonian fluid.Nomenclature h Dimensionless microrotation - j Micro-inertia density - K Dimensionless parameter of vortex viscosity - m Falkner-Skan power-law parameter - Re Reynolds number - T Temperature - u, v Fluid velocities in thex andy directions, respectively - U Free stream velocity - x Streamwise coordinate along the body surface - y Coordinate normal to the body surface Greek symbols Thermal diffusivity - Wedge angle parameter - Spin gradient viscosity - Pseudo-similarity variable - Vortex viscosity - Absolute viscosity of the fluid - v Kinematic viscosity - Dimensionless temperature - Density of the micropolar fluid - Angular velocity of micropolar fluid - Stream function     

Flow past an accelerated horizontal plate in a rotating fluid

Summary A semi-infinite mass of an incompressible viscous fluid bounded by an infinite flat plate is initially rotating with uniform angular velocity about an axis normal to the plate. An analysis is presented for the subsequent flow when the plate started impulsively from rest relative to the rotating fluid moves with uniform acceleration in its own plane. It is found that when 0, the velocity profiles for varying times are nonsimilar in contrast to the velocity profiles which are similar in the absence of rotation (=0). At a given instant, the velocity component along the direction of motion of the plate decreases with an increase in rotation but the transverse velocity component (induced by the Coriolis force) increases with increasing rotation. Due to the gradual thinning of the boundary layer with rotation, both the skin-friction components along and transverse to the direction of motion of the plate increase with increasing rotation. A study of the asymptotic behavior of the velocity field for large time reveals a novel feature of the flow; it develops inertial oscillations with frequency 2, which grow with time. This behavior has not been reported in the absence of rotation.     

Periodic unsteady flows of a non-Newtonian fluid

Summary Exact analytic solutions for the flow of non-Newtonian fluid generated by periodic oscillations of a rigid plate are discussed. Some interesting flows caused by certain special oscillations are also obtained.     

Flow of non-Newtonian fluid between two coaxial cylinders under complex shear conditions

The flow of a non-Newtonian fluid with an exponential rheological equation is investigated in the barrel of an extruder screw with consideration of the presence of circulating motion of the fluid in it.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No. 6, pp. 1069–1076, June, 1970.     

Impregnating a heated filler with a non-Newtonian fluid

An approximate parametric method is used to solve the planar temperature-dependent problem of continuously impregnating a heated filler with a fluid that has a power-law non-Newtonian viscosity.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 61, No. 4, pp. 613–620, October, 1991.     

Flow and heat transfer of a micropolar fluid past a continuously moving porous plate

The boundary layer flow and heat transfer of a micropolar fluid past a semi-infinite porous plate moving continuously is studied. Similarity solutions for the velocity, the temperature, and the microrotation equations are derived. These are shown graphically. The numerical values of the skin-friction coefficient C_f and the rate of heat transfer [?θ'(0)] are entered in tables for different values of suction and injection parameters. The effects of suction and injection, K (the coupling parameter) and G (the microrotation parameter) are discussed.     

Vibrational instability of stationary convection of a non-Newtonian fluid

The stability of stationary convective flow of a non-Newtonian fluid to small perturbations, such as traveling thermal waves, is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 2, pp. 320–325, August, 1978.     

BEM for non-Newtonian fluid flow

The main purpose of this work is to present the use of boundary-domain integral method (BDIM) to analyse the flow behaviour of non-Newtonian fluids. A few available parametric viscosity models are applied representing a non-linear dependence on shear strain rate and shear stress. To evaluate the presented approach the Rayleigh–Benard natural convection was solved at different Rayleigh number values.     

Flow of a viscous fluid at small Reynolds number past a porous sphere with a solid core

Summary Uniform flow of an incompressible viscous fluid at small Reynolds number past a porous sphere of radius a with a solid concentric spherical core of radius b has been discussed. The region of the porous shell is called zone I which is fully saturated with the viscous fluid, and the flow in this zone is governed by the Brinkman equation. The space outside the shell where clear fluid flows is divided into two zones (II and III). In these zones the flow is discussed following Proudman and Pearson's method of expanding Stokes' stream function in powers of Reynolds number and then matching Stokes' solution with Oseen's solution. The stream function of zone II is matched with that of zone I at the surface of the shell by the condition suggested by Ochoa – Tapia and Whitaker. It is found that the drag on the spherical shell increases with the increase of the λ (=b/a) and also with the increase of the Darcy number. The graph of dimensionless drag against λ for various values of Reynolds number shows that the drag increases with the increase of the Reynolds number for all values of λ.     

Lamé-type potentials in a non-Newtonian fluid theory

Summary The existence and completeness of a set of potentials are exhibited in the case of a linear system of coupled differential equations characterizing slow incompressible flow of micropolar fluids. These potentials correspond to the Lamé's potential of classical elasticity.     

Magnetohydrodynamic flow for a non-Newtonian power-law fluid having a pressure gradient and fluid injection

Summary The nonlinear partial differential equation of motion for an incompressible, non-Newtonian power-law fluid flowing over flat plate under the influence of a magnetic field and a pressure gradient, and with or without fluid injection or ejection, is transformed to a nonlinear third-order ordinary differential equation by using a stream function and a similarity transformation.The necessary boundary conditions are developed for flow with and without fluid injection (or ejection), and a solution for four different power-law fluids, including a Newtonian fluid, is presented.The controlling equation includes, as special cases, the Falkner-Skan equation and the Blasius equation.