Steady creeping motion of a liquid bubble in an immiscible viscous fluid bounded by a vertical porous cylinder of finite thickness

The creeping vertical motion of a fluid sphere (drop or gas) or liquid bubbles of different shapes in another immiscible fluid confined by porous boundaries is encountered in several situations in industry and technology. Such flows are generally multi-phase in nature. In this work, we have considered a flow field comprising a non-Newtonian bubble region surrounded by a liquid film of Newtonian fluid. This inner region is bounded by a permeable cylindrical medium pervaded by the same Newtonian fluid. We have studied the interaction features of this multiphase flow in terms of certain practically important geometrical and physical parameters. We have carried out an exact analysis of the governing equations in the three flow fields-Non-Newtonian, Newtonian film and porous regions. The effects of pressure gradient, permeability and rheological parameters on the bubble velocity and the flow in different regions have been discussed

(R1471) MHD Reiner-Rivlin Liquid Flow Through a Porous Cylindrical Annulus

The present work concerns the steady and unsteady flow of an incompressible Reiner- Rivlin liquid in the porous annular region of two concentric rotating cylinders, which is moving parallel to their axis, about the common axis of these cylinders under uniform magnetic field acted in perpendicular direction of the axis. The electrically conducting flow of Reiner-Rivlin liquid in the annular porous region is governed by the Brinkman equation with the consideration that the effective viscosity of liquid is same as viscosity of the liquid. Analytical expressions for velocity components, pressure gradient and volumetric flow rate are established. Effects of the magnetic field and other flow parameters on the axial and rotational velocity components and flow rate are discussed graphically

Drag Experienced by a Composite Sphere in an Axisymmetric Creeping Flow of Micropolar Fluid

This paper concerns an analytical study of a steady axisymmetric uniform flow of an incompressible micropolar fluid past a permeable sphere that contains a solid sphere. The mathematical expression for the flow fields are obtained in terms of stream function by using modified Bessel’s function and Gegenbauer function. No-slip condition, zero microrotation components, continuity of normal velocity which is equal to the filtration velocity on the surface of the sphere are used as boundary conditions. It is assumed that the fluid obeys Darcy law at the permeable surface. The internal and external drag force exerted by the fluid on the sphere, flow rate and the relevant quantities such as pressures, microrotation vectors have been calculated. It is observed that drag is greater for impermeable sphere as compared to permeable sphere. As permeability parameter increases the flow rate also increases rapidly. Various useful results are obtained and compared with the previous particular cases

MHD boundary layer flow of Carreau fluid over a convectively heated bidirectional sheet with non-fourier heat flux and variable thermal conductivity

© 2019 by the authors. In the present exploration, instead of the more customary parabolic Fourier law, we have adopted the hyperbolic Cattaneo-Christov (C-C) heat flux model to jump over the major hurdle of parabolic energy equation . The more realistic three-dimensional Carreau fluid flow analysis is conducted in attendance of temperature-dependent thermal conductivity. The other salient impacts affecting the considered model are the homogeneous-heterogeneous (h-h) reactions and magnetohydrodynamic (MHD). The boundary conditions supporting the problem are convective heat and of h-h reactions. The considered boundary layer problem is addressed via similarity transformations to obtain the system of coupled differential equations. The numerical solutions are attained by undertaking the MATLAB built-in function bvp4c. To comprehend the consequences of assorted parameters on involved distributions, different graphs are plotted and are accompanied by requisite discussions in the light of their physical significance. To substantiate the presented results, a comparison to the already conducted problem is also given. It is envisaged that there is a close correlation between the two results. This shows that dependable results are being submitted. It is noticed that h-h reactions depict an opposite behavior versus concentration profile. Moreover, the temperature of the fluid augments for higher values of thermal conductivity parameters

Axisymmetric Creeping Flow of a Micropolar Fluid over a Sphere Coated with a Thin Fluid Film

Consideration is given to the problem of steady axisymmetric Stokes flow of a micropolar fluid past a sphere coated with a thin, immiscible Newtonian fluid layer. Inertial effects are neglected for both the outer fluid and the fluid film.The stream function solutions of the governing equations are obtained in terms of modified Bessel functions and Gegenbauer functions. The explicit expressions of flow fields are determined by applying the boundary conditions at the coated sphere interface and uniform velocity at infinity. The drag force experienced by the fluid-coated sphere is evaluated and its variation is studied with respect to various geometric and material parameters. It is found that a sphere without coating experience greater resistance in comparison to coated fluid. Some well-known results are then deduced from the present study

Magnetohydrodynamic free convection boundary layer Flow of non-Newtonian tangent hyperbolic fluid from a vertical permeable cone with variable temperature

The nonlinear, non-isothermal steady-state boundary layer flow and heat transfer of an incompressible tangent hyperbolic non-Newtonian (viscoelastic) fluid from a vertical permeable cone with magnetic field are studied. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using the second-order accurate implicit finite difference Keller-box technique. The numerical code is validated with previous studies. The influence of a number of emerging non-dimensional parameters, namely a Weissenberg number (We), rheological power law index (m), surface temperature exponent (n), Prandtl number (Pr), magnetic parameter (M) suction/injection parameter (fw) and dimensionless tangential coordinate (ξ) on velocity and temperature evolution in the boundary layer regime, is examined in detail. Furthermore, the effects of these parameters on surface heat transfer rate and local skin friction are also investigated. It is observed that velocity, surface heat transfer rate and local skin friction are reduced with increasing Weissenberg number, but temperature is increased. Increasing m enhances velocity and surface heat transfer rate but reduces temperature and local skin friction. An increase in non-isothermal power law index (n) is observed to decrease the velocity and temperature. Increasing magnetic parameter (M) is found to decrease the velocity and increase the temperature. Overall, the primary influence on free convection is sustained through the magnetic body force parameter, M, and also the surface mass flux (injection/suction) parameter, fw. The rheological effects, while still prominent, are not as dramatic. Boundary layers (both hydrodynamic and thermal) are, therefore, most strongly modified by the applied magnetic field and wall mass flux effect. The study is pertinent to smart coatings, e.g., durable paints, aerosol deposition processing and water-based solvent thermal treatment in chemical engineering