Effects Of Slip Parameter Research Articles

Time-periodic electroosmotic analysis of couple stress fluid in nanofluidic channels with slippages

This paper investigates the electroosmotic flow of an incompressible couple stress fluid squeezed between two prolonged channels with slippage. An analytical solution is provided for two cases: Poiseuille flow and Couette flow. It investigated how dimensionless parameters affect electroosmotic velocities and volume flow rates, such as slippages, couple stress, frequency, wall zeta potential, and electrokinetic width parameters. In the results, the electroosmotic ‎velocity amplitudes, and volume flow rates decay to zero when the couple stress ‎parameter is zero. The effects of slip parameters, electrokinetic width, characteristic speed, and frequency on the electroosmotic velocity are similar to a Newtonian fluid. Nevertheless, there is a complex relationship between electroosmotic velocity and some of the abovementioned parameters. Previous literature has already resolved the Newtonian and non-Newtonian fluid versions of this problem. In this study, a novel issue involving electroosmotic flow in a couple stress fluid was addressed.

Influence of multiple slips and magnetic effects on the quadratic convective flow over a vertical wedge

AbstractThis paper investigates the quadratic convective flow of Williamson nanoliquid with the impacts of velocity, thermal and concentration slips over a vertical wedge. Further, the magnetic effects and the Buongiorno two‐phase nanoparticle model are considered. The study of this type of flows over a vertical wedge appears in various engineering applications such as thermal insulation, engine parts of vehicles, aerospace, crude oil extraction and heat exchangers. The physical problem is formulated as a set of quadratic coupled partial differential equations (PDEs), which are dimensional. Further, the dimensionless PDEs obtained by the non‐similar transformations are solved with the aid of the implicit finite difference method and the Quasilinearization technique. The effects of slip parameters, streamwise coordinate, fluid material parameters and magnetic field on various gradients and profiles are explored through graphs. The greater values of concentration slip and thermal slip parameters improve the concentration and temperature profiles, but the fluid's velocity is reduced with the velocity slip parameter. The streamwise coordinate significantly influences the fluid's velocity more than the concentration and temperature profiles. The velocity and skin friction coefficient are pronounced more for a higher wedge angle. Also, the numerical results of this investigation compared to similar works that have been published before show that they are very consistent.

Effects of Slip and Inclined Magnetic Field on the Flow of Immiscible Fluids (Couple Stress Fluid and Jeffrey Fluid) in a Porous Channel

In this paper, we study the flow of two immiscible fluids namely, couple stress fluid and Jeffrey fluid in a porous channel. Instead of the classical no-slip conditions on the boundaries, we used slip boundary conditions, which are more realistic and meaningful. In addition, we used inclined magnetic field effects on the fluid flow. The couple stress fluid and Jeffrey fluid are flowing adjacent to each other in the region I and in the region II, respectively, of the horizontal porous channel. The nondimensionalized governing equations are solved analytically by using slip conditions at the lower and upper boundaries and interface conditions at the fluid-fluid interface. The analytical expressions for the velocity components in both regions are obtained in closed form. The effects of slip parameter, Hartmann number, couple stress parameter, Jeffrey parameter, angle of inclination, and Darcy number on velocity components in both regions are investigated. In the absence of slip, couple stress parameter, and Jeffrey parameters, limiting cases are obtained and discussed.

Heat transfer enhancement through nanofluids with applications in automobile radiator

This article investigates the heat transfer enhancement on three different types of nanofluids Titanium dioxide(TiO2), (CuO) Copper oxide and Aluminum oxide (Al2O3) using an application in automobile radiator while considering the slip condition. A comparative study has been carried out for all three nanofluids. The governing partial differential equations are reduced into ordinary differential equations by using similarity transformations. It is observed that the high values of Grashof number leads to decrease in thermal performance of the nanofluid and TiO2 nanofluid affected the most. This study shows that the thermal slip effects leads to a decrease in temperature of the fluid. This decrement is dominant in TiO2 nanofluid whereas CuO has shown least effects of slip parameter. Among all three nanofluids, Al2O3 nanofluid shows the best thermal performance.

On slip of a viscous fluid through proximal renal tubule with linear reabsorption

<p>The hydrodynamical problem of flow in proximal renal tubule is investigated. Axisymmetric flow of viscous, incompressible fluid through the proximal renal tubule that undergoes linear reabsorption with slip at the wall is considered. The stream function is used to transform the governing equations to system of ordinary differential equations. The analytical solutions for velocity components, pressure distribution, fractional reabsorption and the shear stress are found. The effect of slip parameter and reabsorption rate on the flow have been investigated. The points of extreme values for the axial and radial velocity components are identified. The solution is applied to physiological data from human and rat kidney, and the results are presented in tables and graphs.</p>

Effects of Wall Slip on Convective Heat Transfers of Giesekus Fluid in Microannulus

AbstractConvective heat transfer and effect of nonlinear wall slip are studied analytically in concentric microannulus for viscoelastic fluids obeying the Giesekus constitutive equation. Laminar, thermally, and hydrodynamically fully developed flow is considered. A nonlinear Navier model with nonzero slip critical shear stress is employed for the slip equation at both walls. Critical shear stress will cause three slip flow regimes: no slip condition, slip only at the inner wall, and slip at both walls. Thermal boundary conditions are assumed to be peripherally and axially constant fluxes at the walls. Governing equations are solved to obtain temperature profiles and Nusselt number and effects of slip parameters, elasticity, and Brinkman number are discussed. Two regimes are compared when slip occurs at both walls or only at the inner wall. The results indicate that by increasing slip effect and elasticity, heat transfer between wall and fluid is enhanced, but it decreases by increasing Brinkman number. In the case where the heat flux is dominant in the outer wall, the inner wall Nusselt curve shows a singularity for a critical Brinkman number because at this Brinkman number the bulk temperature will be equal to the wall temperature.

Entropy generation and Joule heating of two layered electroosmotic flow in the peristaltically induced micro-channel

We analyze the flow characteristics, thermal behavior, and entropy generation for two layered flow driven by combined effects of electroosmosis and peristaltic pumping in an asymmetric microfluidic channel subjected to velocity and thermal slip conditions. Aqueous solutions having different viscosity and different zeta potentials at the walls of the micro-channel are considered in upper and lower layers to examine the two layered flow variation. This study is motivated towards investigating micro-vascular two layered biofluid flow in capillary, by taking into account of heat transfer effects. Analysis is carried out under suitable physical assumptions (low Reynolds number, long wavelength and low zeta potential). The effects of slip parameter, viscosity, zeta potential and electroosmotic parameter on velocity field and the effects of Joule heating parameter, Brinkman number, thermal slip parameter on temperature field are reported. The variations in Nusselt number based on the velocity and temperature fields, and the variations in Bejan number based on heat transfer irreversibility are also computed. Furthermore, the implications of Joule heating on system irreversibility through entropy generation analysis due to fluid friction and heat transfer are studied. The outcomes of the present study is applicable in designing the thermofluidic micropumps which can be utilized in chemical mixing/separation processes and biomicrofluidics devices for the purpose of diagnosis.

Magneto-Hydrodynamics (MHD) Bioconvection Nanofluid Slip Flow over a Stretching Sheet with Microorganism Concentration and Bioconvection Péclet Number Effects

This study analyzes the effect of slip parameter, microorganism concentration and bioconvection Peclet number on Magneto-hydrodynamics (MHD) bioconvection nanofluid flow over a stretching sheet. Similarity transformation is employed to convert the governing partial differential equations into coupled non-linear ordinary differential equations with appropriate boundary conditions. These equations are solved numerically using fourth order Runge Kutta-Fehlberg integration method along with a shooting technique. The dimensionless velocity, temperature, nanoparticle concentration and density of motile microorganisms were obtained together with the local skin friction, reduced Nusselt, Sherwood and motile microorganism density numbers. It was observed that nanoparticle concentration decreases with increase in the nanoparticle concentration slip but increases as magnetic field parameter increases. Also the velocity of the fluid decreases with increase in both velocity slip parameter ξ and magnetic field parameter M. It is also noticed that the temperature of the flow is continuously decreasing as the value of velocity slip parameter ξ, temperature slip parameter β and concentration slip parameter γ increase. Furthermore, as velocity and nanoparticle concentration slip parameters increase, the Nusselt number was observed to increase while the Sherwood number decreases. The skin friction coefficient also decreases as the values of velocity slip parameter increases. Finally we found that local microorganism transfer rate increases with greater values of bioconvection Lewis number Lb, microorganism concentration Ω and bioconvection Peclet number Pe. Comparisons between the previously published works and the present results reveal excellent agreement.

Combined Effects of Soret and Dufour on MHD Flow of a Power-Law Fluid Over Flat Plate in Slip Flow Rigime

A numerical model is developed to study the Soret and Dufour effects on MHD boundary layer flow of a power-law fluid over a flat plate with velocity, thermal and solutal slip boundary conditions. The governing equations for momentum, energy and mass are transformed to a set of non-linear coupled ordinary differential equations by using similarity transformations. These non-linear ordinary differential equations are first linearized using a quasi-linearization technique and then solved numerically based on the implicit finite difference scheme over the entire range of physical parameters with appropriate boundary conditions. The influence of various governing parameters along with velocity, thermal and mass slip parameters on velocity, temperature and concentration fields are examined graphically. Also, the effects of slip parameters, the Soret and Dufour number on the skin friction, Nusselt number and Sherwood number are studied. Results show that the increase in the Soret number leads to a decrease in the temperature distribution and to an increase in concentration fields.

Forced convection heat transfer of Giesekus fluid with wall slip above the critical shear stress in pipes

Forced convective heat transfer in pipes is investigated for viscoelastic fluids obeying the Giesekus constitutive equation including effect of slip condition by an approximated analytical method. The slip equation at wall is considered as a nonlinear Navier model with non-zero slip critical shear stress. The problem under consideration is steady, laminar and fully developed. Thermal boundary conditions are assumed peripherally and axially constant heat flux at wall. The fluid heating and cooling cases are considered for analysis. Dimensionless temperature profiles and Nusselt number are obtained by solving governing equations and the effects of slip parameters, viscous dissipation and fluid elasticity are discussed. Results show that Nusselt number increases by increasing slip effect but decreases by increasing Brinkman number for the case of fluid heating. However, for the cooling case, the heat generated by viscous dissipation can overcome the effect of wall cooling at first critical Brinkman number and fluid starts to warm up. Also the Nusselt curve shows a singularity in a second critical Brinkman number.

An analysis of hydrodynamic ferrofluid lubrication of an inclined rough slider bearing

The present study aims at analysing the effects of surface roughness, porosity and magnetic field on an inclined slider bearing. The slider bearings mainly are designed for supporting transverse load in an engineering system and enjoy a priority due to its physical wedge pressure generating mechanism. The ferrofluid is being used as lubricant which becomes strongly magnetised in the presence of external magnetic field in a plane inclined rough slider bearing with slip velocity. The earlier studies were related to ferrofluid lubrication based on Shliomis model and it was concluded that the adverse effect of surface roughness was reduced due to magnetisation under the influence of proactive slip parameter. In the present study a space dependent magnetic field of the form has been considered rather than sinusoidal type H2 = KL2 sin (πX). The analysis brings out some interesting results due to change in pattern of magnetic field strength. The pattern of variation of magnetic field considered in the present study contributes to an increase in pressure and load capacity by and load by our conventional lubricant i.e. as that of magnetised lubricant. One interesting finding reported here is that, the adverse effect of slip parameter, reported in earlier studies over load carrying capacity turns rather sinusoidal to be favourable which may be due to the pattern of variation of magnetic field considered in the present study.

English

Slip flow of a second-grade fluid past a lubricated rotating disc is studied. The disc is lubricated with a power-law fluid. The interfacial conditions between fluid and lubricant are imposed on the surface of disc by assuming a thin lubrication layer. The numerical solutions are obtained using Keller-Box method. The effects of slip parameter and Weissenberg number on the three components of fluid velocity and pressure are analyzed graphically while effects on both components of skin friction are demonstrated through tables. The computed results show that spin-up by a second grade bulk fluid near the rotating disc is reduced by increasing slip at the interface. The obtained solutions agree well in the special case with those of other researches. Key words: Non-Newtonian power-law fluid, second grade fluid, rotating disc, slip boundary condition.

Drag on a slip spherical particle moving in a couple stress fluid

The creeping motion of a rigid slip sphere in an unbounded couple stress fluid is investigated. The linear slip boundary condition and the vanishing couple stress condition are applied on the surface of the sphere. A simple formula for the drag force acting on a slip sphere translating in an unbounded couple stress fluid is obtained. Special cases of the deduced drag formula are concluded and compared with analogous results in the literature. The normalized drag force experienced by the fluid on the slip sphere is represented graphically and the effects of slip parameter and viscosity coefficients are discussed.

Nonorthogonal Stagnation-point Flow of a Second-grade Fluid Past a Lubricated Surface

Abstract The stagnation-point flow of a second-grade fluid past a power law lubricated surface is considered in this paper. It is assumed that the fluid impinges on the wall obliquely. A suitable choice of similarity transformations reduces the governing partial differential equations into ordinary differential equations. The thin lubrication layer suggests that the interface conditions between the fluid and the lubricant can be imposed on the boundary. An implicit finite difference scheme known as the Keller-Box method is employed to obtain the numerical solutions. The effects of slip parameter and Weissenberg number on the fluid velocity and streamlines is discussed in the graphs. The limiting cases of partial-slip and no-slip can be deduced from the present solutions.

Rotary oscillation of a composite sphere in a concentric spherical cavity using slip and stress jump conditions

The rotary oscillation of a composite sphere, consisting of a solid core surrounded by a porous shell, in an incompressible viscous fluid bounded by a concentric spherical cavity is investigated using the Brinkman model. The stress jump condition is applied on the porous-fluid interface and the slip boundary condition is proposed on the surface of the spherical cavity. The couple exerted by the fluid on the porous surface is obtained analytically and its imaginary and real coefficients are represented graphically. The effects of slip parameter, permeability coefficient, stress jump coefficient and effective viscosity ratio on the torque are discussed and special cases are deduced.

Rigid Rotor Stability Analysis on Finite Hydrostatic Double-Layer Porous Oil Journal Bearing with Velocity Slip

A theoretical investigation has been carried out for stability characteristics of a finite hydrostatic double-layer porous oil journal bearing considering the effect of Beavers-Joseph velocity slip at the porous film interface. A linearized perturbation method has been used to obtain the threshold of stability in terms of critical mass parameter. The effect of slip parameters, eccentricity ratios, bearing feeding parameter, and slenderness ratio on the stability is investigated. Furthermore, nonlinear transient analysis is carried out to determine the system stability by tracing the journal center locus. Several trajectories of the journal center locus have been obtained for different operating conditions and are depicted with the help of graphics.

Effect of permeability and different slip velocities at both the porous interface using couple stress fluids on the slider bearing load carrying mechanism

In this paper, a theoretical analysis for the inclined slider bearing with porous layer attached to slider as well as stator including effects of slip parameter in the x-direction for the upper and lower porous regions with different permeability parameters and couple stresses has been studied. The modified Reynolds equation governing fluid film pressure is derived on the basis of Stokes microcontinuum theory of couple stress fluids by using slip boundary conditions at the fluid–porous interface. The modified Reynolds equation is solved analytically and closed form expressions are obtained for the fluid film pressure, load capacity, friction on the slider, and coefficient of friction to examine possible effects on the system. Computed values of load capacity, friction on the slider and coefficient of friction are displayed in graphical form.

Peristaltic Creeping Flow of Power Law Physiological Fluids through a Nonuniform Channel with Slip Effect

A mathematical study on creeping flow of non-Newtonian fluids (power law model) through a nonuniform peristaltic channel, in which amplitude is varying across axial displacement, is presented, with slip effects included. The governing equations are simplified by employing the long wavelength and low Reynolds number approximations. The expressions for axial velocity, stream function, pressure gradient, and pressure difference are obtained. Computational and numerical results for velocity profile, pressure gradient, and trapping under the effects of slip parameter, fluid behavior index, angle between the walls, and wave number are discussed with the help of Mathematica graphs. The present model is applicable to study the behavior of intestinal flow (chyme movement from small intestine to large intestine). It is also relevant to simulations of biomimetic pumps conveying hazardous materials, polymers, and so forth.

Effect of Slip Parameter on the Flow of Viscous Fluid Past an Impervious Sphere

In this paper, the uniform flow of an incompressible, axi-symmetric, viscous fluid over a stationary impervious sphere with interface slip on its surface is considered. ＂Homotopy Analysis Method＂ (HAM) is used to solve the non linear momentum equations for stream function. To match with the uniform flow far away from the sphere, stream function is taken in terms of Gegenbauer polynomials. The solution obtained is found to be convergent and is seen to be in good agreement with the results available in literature. Drag acting on the sphere due to the flow and vorticity functions is found. For different values of the slip parameter, drag acting on the sphere is evaluated and the results are in good agreement with the available experimental data for the Reynolds numbers less than 50. Expansion of Gegenbauer polynomials and solution of the problem are obtained using MATHEMATICA.

Analysis of Slip Induced One Dimensional MHD Flow between Parallel Plates

Fluid drag is an important phenomenon at solid-liquid interface. In nano/microfluidics, it has significant importance due to small surface to volume ratio. Slip at the interface is an important phenomenon which reduces the friction at the interface. In this study we have proposed a more general theoretical model for the slip induced magneto-hydrodynamic (MHD) flow across parallel plates. We have analyzed the effect of slip parameter on the velocity and the flow rate across parallel plates. The effect of magnetic field on velocity and the flow rate has also been discussed. Our results show satisfactory agreement with the previously conducted experimental and analytical studies. In this paper, we have briefly discussed and compared the new model with the existing experimental and theoretical studies.