non-Newtonian Couple Stress Fluid Research Articles

Natural convective and Cattaneo–Christov model for couple stress nanofluid at the middle of the squeezed channel with sensor surface

The aim of this work is to present a natural convective and squeezing flow model of two-dimensional couple stress nanofluid which is flowing on the sensory surface with variable fluid viscosity. The fluid flowing on a microcantilever sensory surface and squeezing is happening at free stream. The sensor is also useful to detect the movement of fluid and the variations in thermal and solutal rates. The Cattaneo–Christov model is adopted along with nanoparticle and chemical reaction to explore the transmission of heat and mass rates. The analysis of heat transmission in non-Newtonian couple stress fluid flowing on squeezed sensory surface by using the Cattaneo–Christov heat conduction model has various industrial and scientific applications including the polymer processing, wastewater treatment, chemical reactors, biomedical flows, cooling and heating processes in industries, heat exchangers, microfluidics, oil and gas industries. All the assumptions are applied in the basic governing laws laws and then we get the model of the partial differential equations. The governing model of equations is transmuted into ordinary differential equations form via the transformations and then the numerical results of these ODE’s are examined with a well-defined numerical technique “Shooting Method”. For higher inputs of couple stress, squeezing index and permeability velocity, the fluid’s internal velocity decreases. Because of the Prandtl number and thermal relaxation coefficient, the heat transfer mechanism slows down. Mass transfer increases for greater inputs of the thermal diffusivity coefficient and decreases due to concentration relaxation. Further, the numerical dependency of emerging parameters on the skin friction is illustrated in tabular form. The parametric effects on the model (velocity, temperature and concentration) are introduced using numerical values shown in the table.

Statistical Analysis of Non-Newtonian Couple Stress Fluid Induced in Stretching Cylinder

The paper provides the impact of suction and injection on convection laminar incompressible couple stress fluid flow and magnetic field using spectral quasi linearization methods as the major novelty of our work. This work is to addresed heat transfer is an important process in many engineering, industrial, residential, and commercial buildings. Thus, this study aims to analyze the effect of MHD and non-Newtonian couple stress fluid runs over a permeable stretched cylinder. The leading formulation is transmuted into ordinary differential equations via similarity functions. The coupled equations with non-linearly terms are resolved numerically through utilization of MATLAB code for spectal quasi linearization methods (SQLM). Convergence regions for solutions are discussed. Graphical results illustrating the impacts of various emerging parameters are presented in discussion. The statistical declaration and probable error for skin friction and Nusselt number are numerically computed and discussed through Tables. From obtained outcomes it is concluded that magnitude of skin friction increases at the cylindrical surface for higher values of couple stress parameter and Reynolds number. Nusselt number or heat transfer rate also enhances at the surface of cylinder in the presence of Reynolds number.

Channel flow of non-Newtonian fluid due to peristalsis under external electric and magnetic field

The overall objective of the current analysis is to examine how electroosmotic flow combined with peristaltic pumping phenomenon could ably contribute to intracellular fluid flow. The biofluid is taken as non-Newtonian Couple stress fluid, while micro-passage is approximated as two-dimensional inclined channel comprehending complex peristaltic walls. Following a traditional approach of peristaltic fluid flow problem balance of mass and momentum is utilized. Beside channel waves, flow is also generated by Lorentz force triggered by electric and magnetic fields. To integrate electric potential term Poisson-Boltzmann and Nernst Planck equation are utilized. Finally, a sixth order BVP in term of stream function is obtained by employing creeping flow, long wavelength and Debye-Hückel assumptions. A numerical solution is calculated and analyzed by plotting fluid velocity and level curves in MATLAB 2021b. It is observed that couple stress fluid flows with greater speed (in central region of the channel) as compared to Newtonian fluid. Moreover, electro-osmotic parameter and Debye-Hückel length are assistive factors to the fluid velocity in the lower half of the passage.

Buoyancy driven flow of a couple stress fluid from an isothermal vertical plate: the role of spatially periodic magnetic field

The present article deals with the analysis of the buoyancy-driven flow of a non-Newtonian couple stress fluid from an isothermal vertical plate under the influence of a spatially periodic magnetic field. We consider, in this work, the applied magnetic field to be a sinusoidal function of axial coordinate. We solve the coupled nonlinear governing equations numerically consistent with the help of an implicit Crank-Nicolson finite difference scheme. We analyse the impact of periodic magnetic field on the flow velocity of couple stress fluid and its eventual consequence on the convective transport of heat. The flow variables governing the underlying thermo-magneto-hydrodynamics are examined graphically in terms of velocity, temperature distribution, and friction-factor coefficients. The result indicates that the magnitude of the velocity and temperature increases for increasing the magnitude of the couple stress parameter, attributed primarily to the enhanced resistance due to larger degree collision of couple stress fluid particles. On the other hand, the local skin friction coefficient and heat transfer rate reduces owing to the adverse effect of the Lorentz force due to the applied magnetic field.

Numerical Simulation of Nonlinear Thermal Radiation on the 3D Flow of a Couple Stress Casson Nanofluid Due to a Stretching Sheet

Abstract Little is known on the three-dimensional flow of a couple stress Casson fluid conveying nanoparticles when the significance of Lorentz force, chaotic gesture of those minute particles, and thermophoresis are significant. The intent of this investigation is to focus on the flow of such fluid along a horizontal surface due to dual stretching and internal heating. A zero nanoparticle mass flux condition is employed at the surface, which specifies that the nanoparticles’ fraction is submissively measured. The dimensional nonlinear equations are reduced into a system of coupled nonlinear ordinary differential equations by employing scaling analysis and later they are solved numerically. The results are discussed graphically for various emerged physical parameters through different plots. The results in the absence of stretching ratio factor indicate that the heat absorption parameter and Prandtl number accelerate the heat transfer rate. The temperature of the non-Newtonian couple stress fluid is found to be higher than that of viscous case. It may be suggested that the Casson couple stress nanofluid can be substituted for the corresponding viscous fluid in industrial applications for greater heat transfer. The outcomes are closely matched with the studies available in the literature as a limiting case.

Non-Newtonian Couple Stress Fluid with MHD and Viscosity Variation in Conical Bearing

Non-Newtonian Couple Stress Fluid with MHD and Viscosity Variation in Conical Bearing

Flow analysis of biconvective heat and mass transfer of two-dimensional couple stress fluid over a paraboloid of revolution

In this paper, two-dimensional non-Newtonian couple stress fluid flow over the upper horizontal surface of a paraboloid (uhsp) (shaped like a submarine or any aerodynamical automobile) is investigated. At the freestream, a stretching of the fluid layer is assumed along with catalytic surface reaction which tends to induce the flow in the fluid-saturated domain. The problem is modeled by engaging laws of conservation for mass, momentum, heat and concentration. Velocity components are converted to stream functions and similarity transformations to reduce the dependent and independent variables in the partial differential equation describing the flow. Stream functions ideally satisfy continuity equation and transformation to reduce the PDEs to the system of coupled nonlinear ODEs. The numerical solution of these equations is obtained using the shooting-RKF method. The graphical results show that both the lateral and horizontal velocities decrease by increasing the couple stress material parameter and cause the temperature to rise. The thermal boundary layer decreases subject to the thickness parameter and has appositive effects on concentration boundary layer. Finally, numerical results have also been tabulated.

Biomechanics of electro-kinetically modulated peristaltic motion of bio-fluid through a divergent complex wavy channel

The utility of electrically-driven peristaltic flow to enhance the mechanical efficiency of a biological system is diverse. This motivates us to discuss the mathematical modelling of magnetic fluid flow via complex wavy walls. Additionally, an electric field is also applied in the axial direction. The non-Newtonian couple stress fluid model is used here. The analysis is performed under the Debye–Hückel linearization. The governing equations are modelled under long wavelength and low Reynolds number assumptions. A closed form solution is obtained for the stream function, which is further used to calculate other physical quantities. To observe the remarkable effects of eminent parameters on the velocity distribution and volumetric flow rate, we have plotted graphs in both the two- and three-dimensional axes. A comparison between the simple and complex peristaltic waves is also provided. This study is very useful for designing a non-uniform microperistaltic pump in which flow can be controlled by electromagnetic forces.

Couple Stresses and Thermophoresis Influences on Free Convective Heat and Mass Transfer of Viscoelastic Fluid with Hall and Ion-Slip Effects.

An analysis is presented to investigate the Hall and Ion-slip effects on non-Newtonian couple stress fluid flow between vertical channel in the presence of thermophoresis phenomena. The considered fluid obeys to the viscoelastic second-grade model. The problem is modulated mathematically to describe continuity, momentum, temperature, and concentration equations. The influences of physical parameters of dimensionless equations of velocity components () and (), temperature () and concentration () have been shown in some of figuthe res, as well as skin friction (), Nusselt number() and Sherwood number() have been computed. It is found that the velocity decreases with increasing in Hall parameter and Ion slip parameters.

Linear and Weakly Nonlinear Double-Diffusive Magnetoconvection in a Non-Newtonian Fluid Layer

The linear and weakly nonlinear stability of a doubly diffusive electrically conducting non-Newtonian couple stress fluid layer in the presence of a uniform vertical magnetic field is investigated. The system behaves like a triply diffusive one with the magnetic field as a third diffusing component. Several remarkable departures from those of doubly diffusive couple stress fluid systems are recognized and the implications of couple stresses on the same are explored. By performing the linear stability analysis, it has been recognized that (i) oscillatory convection occurs even if the diffusivity ratios are greater than unity, (ii) the bottom-heavy solute gradient in the presence of magnetic field, as well as magnetic field in the presence of bottom-heavy solute gradient, destabilize the system under certain conditions, (iii) disconnected closed oscillatory neutral curves occur for certain choices of physical parameters indicating the necessity of three critical values of thermal Rayleigh number to specify the linear stability criteria instead of the usual single value. A weakly nonlinear stability analysis has been performed using modified perturbation theory and the steady bifurcating equilibrium solution is found to be subcritical in some parameter space. Heat and mass transports are calculated in terms of Nusselt numbers and the influence of physical parameters on the same is discussed in detail.

Thermal explosion and irreversibility of hydromagnetic reactive couple stress fluid with viscous dissipation and Navier slips

The study examines the thermal explosion branched-chain and entropy generation as a result of irreversibility of hydromagnetic reactive couple stress liquid with viscous heating and Navier slips. The reactive fluid flow is enhanced by heat dependent pre-exponential factor and axial pressure gradient in a porous wall. The flow equations for the non-Newtonian couple stress fluid model and heat transfer are solved by employing a semi-analytical collocation weighted residual method (CWRM). The efficiency and validity of the obtained results was verified with the existing results. The results reveal that at low hysteresis magnetic and viscous dissipation the irreversibility process is minimized and thermodynamic equilibrium is improved. The results from this study can assist in understanding the relationship between thermal and thermal explosions branched-chain.

Thermally Charged MHD Bi-Phase Flow Coatings with Non-Newtonian Nanofluid and Hafnium Particles along Slippery Walls

The present study is about the pressure-driven heated bi-phase flow in two slippery walls. The non-Newtonian couple stress fluid is suspended with spherically homogenous metallic particles. The magnetic susceptibility of Hafnium allures is taken into account. The rough surface of the wall is tackled by lubrication effects. The nonlinear coupled partial differential equations along with the associated boundary conditions are first reduced into a set of ordinary differential equations by using appropriate transformations and then numerical results were obtained by engaging the blend of Runge–Kutta and shooting techniques. The sway of physical quantities are examined graphically. An excellent agreement within graphical illustration and numerical results is achieved.

Effects of pressure distribution on parallel circular porous plates with combined effect of piezo-viscous dependency and non-Newtonian couple stress fluid

Piezo-viscous effect i.e., Viscosity-pressure dependency has an important part in the applications of fluid flows like fluid lubrication, micro fluidics and geophysics. In this paper, the joint effects of piezo-viscous dependency and non-Newtonian couple stresses on the performance of circular porous plate’s squeeze film bearing have been studied. The results for pressure with various values of viscosity-pressure parameters are numerically calculated and compared with iso-viscous couple stress and Newtonian lubricants. Due to piezo-viscous effect, the pressure with piezo-viscous Non-Newtonian is significantly higher than the pressure with iso-viscous Newtonian and iso-viscous Non-Newtonian fluid.

ON THE STATIC ANALYSIS OF ANNULAR RINGH HYDROSTATIC THRUST BEARINGS LUBRICATED WITH COUPLE STRESS FLUIDS

In the present theoretical analysis, the static properties of the annular ring hydrostatic thrust bearings have been investigated. The lubricant in the system has been taken as non-Newtonian couple stress fluids. The effects of centrifugal inertia and couple stresses on the film pressure, load capacity and lubricant flow rate have been studied and a good agreement of the present results with the earlier established results has been observed. Analytic solution for pressure distribution has been obtained in the analysis taking into account, the influence of centrifugal inertia in the recess region. The effect of couple stress on pressure was found to be dependent on central recess radius but the decreasing load capacity and flow rate with the increase of couple stress parameter was observed in the analysis. Load capacity was also observed to be higher with the recess radius closer to the axis of the bearing.

Nonlinear stability boundary of journal bearing systems operating with non-Newtonian couple stress fluids

The non-Newtonian effects on the nonlinear stability boundary of short journal bearings are investigated through the transient nonlinear analysis. Two coupled nonlinear equations are solved by using the fourth-order Runge-Kutta method. According to the results, there exists a nonlinear stability boundary within the clearance circle. Any initial positions of the shaft center outside of this boundary would yield an unstable trajectory, even though the bearing should be stable in accordance with the linear stability theory. The non-Newtonian effects provide a larger stability boundary within the clearance circle as compared to the bearing lubricated with a Newtonian fluid.

A Study of Creeping Sinusoidal Flow of Bio-Rheological Fluids through a Two-Dimensional High Permeability Medium Channel

The creeping sinusoidal flow of non-Newtonian couple stress fluids in a two-dimensional porous medium channel with deformable walls, is investigated as a model of peristaltic physiological gastric transport. A mathematical model is developed which is also applicable to hemodynamics of diseased arteries. The assumptions of long wavelength and low Reynolds number approximation are employed for creeping (viscous-dominated) flow. Solutions for axial velocity, volumetric flow rate, pressure gradient and stream function are obtained. The influence of couple stress rheological parameter and permeability parameter on velocity profile, pressure gradient and stream lines patterns are computed with the aid of Mathematica Software. Keywords: Sinusoidal wave propagation, Couple stress fluid, Porous channel, Stream lines, Cerebral diseased hemodynamics, Gastric flow. Read more →

Squeeze Film Problems of Long Partial Journal Bearings for Non-Newtonian Couple Stress Fluids with Pressure-Dependent Viscosity

Abstract According to the experimental work of C. Barus in Am. J. Sci. 45, 87 (1893) [1], the dependency of liquid viscosity on pressure is exponential. Therefore, we extend the study of squeeze film problems of long partial journal bearings for Stokes non-Newtonian couple stress fluids by considering the pressure-dependent viscosity in the present paper. Through a small perturbation technique, we derive a first-order closed-form solution for the film pressure, the load capacity, and the response time of partial-bearing squeeze films. It is also found that the non-Newtonian couple-stress partial bearings with pressure-dependent viscosity provide better squeeze-film characteristics than those of the bearing with constant-viscosity situation.

MHD couple stress squeeze film characteristics between sphere and plane surface

In this paper, the effect of non-Newtonian couple stress fluids on the magnetohydrodynamic (MHD) squeeze film characteristics between a sphere and a plane surface is analysed. By taking into account the couple stresses due to the presence of microstructure additives in the lubricant and the magnetic effects due to the magnetisation of the couple stress fluid, the non-Newtonian couple stress MHD Reynolds type equation is derived. The numerical solutions for the MHD squeeze film characteristics are presented for various values of couple stress parameter, and magnetic Hartmann number. The results indicate that the influences of couple stresses and the magnetic effects on the squeeze film characteristics are significantly apparent. It is concluded that the MHD couple stress fluids have better lubricating qualities than the corresponding Newtonian case.

Combined effects of non-Newtonian rheology and rotational inertia on the squeeze film characteristics of parallel circular discs

The combined effects of non-Newtonian couple stresses and rotational inertia on the squeeze film behaviours between parallel rotating circular discs have been analysed in this paper. On the basis of Stokes micro-continuum theory, the non-Newtonian Reynolds-type equation including the rotational inertial effects is derived, and applied to predict the squeeze film performance. According to the results obtained and discussed, the effects of rotational inertia yield a lower squeeze-film load-carrying capacity; however, the presence of non-Newtonian couple stresses provides an increase in the load-carrying capacity and the approaching time. Better squeeze film characteristics of rotating circular discs are achieved by the use of a non-Newtonian couple stress fluid.

Derivation of non-Newtonian squeeze-film Reynolds equation between convex surfaces and application to two different cylinders

The derivation of non-Newtonian squeeze-film Reynolds-type equation between two convex surfaces and its application are of interest in the present study. Based upon the Stokes micro-continuum theory, the non-Newtonian squeeze-film Reynolds-type equation between two convex surfaces is derived to take into account the effects of couple stresses resulting from the lubricant blended with various additives. This non-Newtonian squeeze-film Reynolds-type equation is applicable to squeeze-film bearings lubricated with couple stress fluids when the general upper film shape and the lower film shape are specified. To guide the use of the equation, the squeeze-film mechanism between two different cylinders of infinite width with non-Newtonian couple stress fluids is illustrated. Comparing with the Newtonian-lubricant case, the presence of non-Newtonian couple stresses provides an increase in the load-carrying capacity, and therefore lengthens the approaching time. In addition, the effects of couple stresses on the squeeze film characteristics are more pronounced at lower squeeze-film height with larger couple stress parameters and larger radius ratios of cylinders. As the value of radius ratio approaches infinity, the present results agree closely with those of the previous studies by Hamrock [6] and by Lin et al. [19], respectively; it provides a support to the present study.