Effects Of Slip Parameter Research Articles

Combined Effect of Buoyancy Force and Navier Slip on Entropy Generation in a Vertical Porous Channel

In this paper, we investigate the combined effects of buoyancy force and Navier slip on the entropy generation rate in a vertical porous channel with wall suction/injection. The nonlinear model problem is tackled numerically using Runge–Kutta–Fehlberg method with shooting technique. Both the velocity and temperature profiles are obtained and utilized to compute the entropy generation number. The effects of slip parameter, Brinkmann number, the Peclet number and suction/injection Reynolds number on the fluid velocity, temperature profile, Nusselt number, entropy generation rate and Bejan number are depicted graphically and discussed quantitatively.

MHD coupled-flow and heat transfer across a porous layer due to an oscillating plate with radiation

This paper deals with the MHD unsteady coupled-flow of a viscous, incompressible, electrically conducting Newtonian fluid past an infinite horizontal impermeable oscillating plate at the bottom of a porous layer of finite thickness when the no-slip condition between the plate and the fluid is no longer valid. For investigating the associated heat transfer problem, the viscous dissipation, Ohmic dissipation and radiation effects are also included in the energy equation. Inclusion of velocity and temperature partial slips modifies the governing boundary conditions from linear to non-linear relations. The problem of flow and heat transfer is solved numerically using Crank–Nicolson implicit finite difference scheme. For an optically-thin medium having relatively low density, the Cogley equilibrium model is used to simulate radiative heat transfer. The effects of slip parameters, Darcy number, magnetic field and radiation parameter on the velocity distribution, temperature distribution, skin friction and rate of heat transfer are investigated and discussed.

PULSATILE MOTION OF BLOOD IN A CIRCULAR TUBE OF VARYING CROSS-SECTION WITH SLIP FLOW

Pulsatile motion of blood in a circular tube of varying cross-section has been developed by considering slip flow at the tube wall and the blood to be a non- Newtonian biviscous incompressible fluid. The tube wall is supposed to be permeable and the fluid exchange across the wall is accounted for by prescribing the normal velocity of the fluid at the tube wall. The tangential velocity of the fluid at the tube wall is also accounted in the present investigation. A perturbation technique has been carried out for low Reynolds number flow and for small amplitude of oscillation. The effects of slip parameter, leakage parameter, Reynolds number and apparent viscosity coefficient on the streamlines, wall shear stress and pressure drop have been discussed and shown graphically for suction and injection respectively.

HEAT TRANSFER DUE TO MHD SLIP FLOW OF A SECOND-GRADE LIQUID OVER A STRETCHING SHEET THROUGH A POROUS MEDIUM WITH NONUNIFORM HEAT SOURCE/SINK

An analysis is carried out to study the heat transfer characteristics of a second-grade non-Newtonian liquid due to a stretching sheet through a porous medium under the influence of external magnetic field. The stretching sheet is assumed to be impermeable. Partial slip condition is used to study the flow behavior of the liquid. The effects of viscous dissipation, nonuniform heat source/sink on the heat transfer are addressed. The nonlinear partial differential equations governing momentum and heat transfer in the boundary layer are converted into nonlinear ordinary differential equations using similarity transformation. Analytical solutions are obtained for the resulting boundary value problems in the case of two types of boundary heating, namely, constant surface temperature (CST) and prescribed surface temperature (PST). The effects of slip parameter, second-grade liquid parameter, combined (magnetic and porous) parameter, Prandtl number, Eckert number, and nonuniform heat source/sink parameters on the heat transfer are shown in several plots. Analytical expressions for the wall frictional drag coefficient and wall temperature gradient are obtained.

Slip effects on shearing flows in a porous medium

This paper deals with the magnetohydrodynamic (MHD) flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy’s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.

The partially wetted bearing—extended Reynolds equation

The artificial no-slip boundary conditions on the liquid/solid interfaces are traditionally used widely. Due to the advances on the measurement technique and interface sciences, the applications of no-slip boundary conditions on micro-systems are challenged continuously. The ‘slip effects’ are observed in small clearance measurement or by treating the surfaces hydrophobic. The non-Newtonian power-law fluid as well as the Navier-slip boundary conditions is considered in the partially wetted bearings. A perturbation technique is utilized to derive the extended Reynolds equations. The analysis applied either to Couette–dominated highly non-Newtonian fluids, or to Newtonian fluids with arbitrary Couette-Poiseuille components. Finally, the effects of slip parameters on the bearing performances are discussed.

Blood flow in capillary under starling hypothesis

A perturbation solution of the flow of blood in the microcirculation by taking into account the influence of slip velocity at the membrane surface is presented. It is assumed that the exchange of fluid across the capillary wall obeys Starling’s hypothesis, that is, the rate of flow per unit area through the wall surface is proportional to the difference between the pressure of the fluid within and outside of the capillary. The expressions for the velocity and pressure distributions within the tube are obtained. Discussions are made from a physiological point of view. The effect of slip parameter is discussed with the help of graphs.

Viscous heating in nonisothermal die flows of viscoplastic fluids with wall slip

Analytical solutions are developed for the viscous heating in slit and cylindrical tube die flows of viscoplastic fluids subject to slip at the wall. Closed-form expressions for the velocity and temperature distributions, as well as the bulk temperature, valid from the entrance to the exit of the die are presented. The problem of solving the equation of conservation of energy is transformed to that of solving an eigenvalue problem using the finite integral transform technique; as many eigenvalues and eigenfunctions as needed are determined using the sign count method. The accuracy of the solutions is established and the effects of slip parameter, apparent yield stress, and Griffith number on viscous heating are examined. The solutions can be used for estimating pressure drop, and temperature rise in die flows of viscoplastic fluids with or without wall slip occurring at the walls.

The movement of single large liquid bubbles in vertical porous tubes

The motion of single large liquid bubbles (exhibiting micropolar behaviour) surrounded by a liquid under gravity in closed vertical porous tube has been studied. The effect of slip parameter and porosity parameter has been studied on pressure gradient, velocity distribution for given film thickness. A possible application of the result for detecting the pressure fluctuations of a human body has been suggested.