A comparative study on the rheological properties of upper convected Maxwell fluid along a permeable stretched sheet.

The objective of this paper is to examine the flow of a non-Newtonian Maxwell fluid induced by a permeable stretching sheet in motion within a porous medium. The research incorporates the Cattaneo-Christov heat flux model to study the heat transfer process. The utilization of the Cattaneo-Christov heat flux approach becomes relevant in scenarios involving materials with high thermal conductivity or during short time intervals. Consequently, the current investigation holds significant importance. It is assumed that the viscosity of the Maxwell fluid changes exponentially as the temperature changes. The modeling of the physical phenomena being investigated takes into account the effects of a magnetic field, thermal radiation, velocity, and thermal slip conditions. In this study, the viscous dissipation phenomenon is taken into account because it can have notable impacts on the temperature and viscosity of the fluid, and is known to play a crucial role in fluid flow phenomena. The equations developed to model fluid flow are transformed into nonlinear ordinary differential equations through the use of appropriate similarity transformations. The focus of the research revolves around investigating the numerical solution of ordinary differential equations accompanied by boundary conditions using the shooting technique. The findings are then showcased via tables and graphs and scrutinized in order to arrive at conclusions. Furthermore, the precision of the present findings was evaluated by contrasting the heat transfer rate with outcomes that were previously published. Based on the obtained outcomes, it can be concluded that both the Eckert number and thermal radiation have a comparable enhancing influence, whereas the thermal relaxation parameter and thermal slip parameter exhibit opposing effects.

The Role of Nanofluids in Renewable Energy Engineering.

The phenomenon of nanofluid flows is intrinsically characterized by several scales and intricate physical processes [...].

Assorted kerosene-based nanofluid across a dual-zone vertical annulus with electroosmosis.

The goal of this numerical simulation is to visualize the electroosmotic flow of immiscible fluids through a porous medium in vertical annular microtubes. The inner region (Region I) is filled with an electrically conducting hybrid nanofluid while an electrically conducting Jeffrey fluid is flowing in the second region (Region II). The chosen nanofluid is kerosene-based and the nanoparticles (Fe3O4-TiO2) are of a spherical shape. A strong zeta potential is taken into account and the electroosmotic velocity in the two layers is considered too. The annular microtubes are subjected to an external magnetic field and an electric field. The linked nonlinear governing equations with initial, interface and boundary conditions are solved using the finite difference method. The wall zeta potential and EDL thickness on the electric potential distribution, the velocity profile, the volumetric flow rate and the heat transfer are investigated versus the parameters under consideration. Graphs have been used to describe the numerical results of numerous emerging factors. It has been noticed that the temperature is the least for the clear fluid than the that of the non-clear one. Due to the fact that oil-based nanofluids are utilized to improve the stability and thermophysical characteristics of nanofluids when they are subjected to high temperatures, the proposed study presents a mathematical assessment that is sought to be useful in oil-based nanoflows' applications.

Unraveling the nature of nano-diamonds and silica in a catheterized tapered artery: highlights into hydrophilic traits.

In this work, we observe the behavior of a hybrid nanofluidic model containing nanodiamonds and silica nanoparticles. The nanofluid propagates through a catheterized tapered artery with three distinct configurations: converging tapered, non-tapered and diverging tapered arteries. In order to assess the rheological properties of the blood, the third-grade non-Newtonian fluid is employed in the flow model such that the Newtonian versus non-Newtonian effects are revealed. The system of equations governing the flow is modeled under magnetic field and with heat transfer, then solved in a closed form using the perturbation approach for the pertinent parameters. The interpretations of the physical variables of interest, such as the velocity, temperature and wall shear stress, are explained. The integration of diamonds and silica nanoparticles give rise to diverse of biological applications since they are used in the drug delivery and biological imaging in genetic materials due to their hydrophilic surfaces. The present mathematical analysis lays a solid foundation on possible therapeutic applications in biomedicine.

Computational Framework of Magnetized MgO-Ni/Water-Based Stagnation Nanoflow Past an Elastic Stretching Surface: Application in Solar Energy Coatings.

In this article, motivated by novel nanofluid solar energy coating systems, a mathematical model of hybrid magnesium oxide (MgO) and nickel (Ni) nanofluid magnetohydrodynamic (MHD) stagnation point flow impinging on a porous elastic stretching surface in a porous medium is developed. The hybrid nanofluid is electrically conducted, and a magnetic Reynolds number is sufficiently large enough to invoke an induced magnetic field. A Darcy model is adopted for the isotropic, homogenous porous medium. The boundary conditions account for the impacts of the velocity slip and thermal slip. Heat generation (source)/absorption (sink) and also viscous dissipation effects are included. The mathematical formulation has been performed with the help of similarity variables, and the resulting coupled nonlinear dimensionless ordinary differential equations have been solved numerically with the help of the shooting method. In order to test the validity of the current results and the convergence of the solutions, a numerical comparison with previously published results is included. Numerical results are plotted for the effect of emerging parameters on velocity, temperature, magnetic induction, skin friction, and Nusselt number. With an increment in nanoparticle volume fraction of both MgO and Ni nanoparticles, the temperature and thermal boundary layer thickness of the nanofluid are elevated. An increase in the porous medium parameter (Darcy number), velocity slip, and thermal Grashof number all enhance the induced magnetic field. Initial increments in the nanoparticle volume fraction for both MgO and Ni suppress the magnetic induction near the wall, although, subsequently, when further from the wall, this effect is reversed. Temperature is enhanced with heat generation, whereas it is depleted with heat absorption and thermal slip effects. Overall, excellent thermal enhancement is achieved by the hybrid nanofluid.

Electro-magnetically modulated self-propulsion of swimming sperms via cervical canal.

The purpose of this study is to theoretically investigate the electro-magneto-biomechanics of the swimming of sperms through cervical canal in the female reproductive system. During sexual intercourse, millions of sperms migrate into the cervix in large groups, hence we can approximately model their movement activity by a swimming sheet through the electrically-conducting biofluid. The Eyring-Powell fluid model is considered as the base fluid to simulate male's semen with self-propulsive sperms. An external magnetic field is applied on the flow in transverse direction. The governing partial differential system of equations is analytically solved. Creeping flow regimen is employed throughout the channel due to self-propulsion of swimmers along with long wavelength approximation. Solutions for the stream function, velocity profile, and pressure gradient (above and below the swimming sheet) are obtained and plotted with the pertinent parameters. The prominent features of pumping characteristics are also investigated. Results indicate that the propulsive velocity is reduced with an increase in the electric field which is an important feature that can be used in controlling the transport of spermatozoa inside the cervical canal. Not only is the present analysis valid for living micro-organisms, but also valid for artificially designed electro-magnetic micro-swimmers which is further utilized in electro-magnetic therapy taking place in female's lubricous cervical canal filled with mucus.

Adverse effects of a hybrid nanofluid in a wavy non-uniform annulus with convective boundary conditions.

The presented investigation theoretically studies the physical characteristics of a two-dimensional incompressible hybrid nanofluid in a non-uniform annulus where the boundaries are flexible. A mixed convective peristaltic mechanism is implemented to model blood-based nanofluids using two different nanoparticles (Ag + Al2O3). Convective boundary conditions are employed and different forms of nanoparticles are discussed (bricks, cylinders and platelets). The problem is shortened by engaging a lubrication method. Exact expressions for the temperature of cumulative heat source/sink standards, hemodynamic velocity, pressure gradient and streamlines of different shapes of nanoparticles are obtained. Special cases of pure blood and the Al2O3 nanofluid of our model are derived. A comparison is set between nanofluids and hybrid nanofluids from which we observed variations in heat transfer rate in different regions due to the oscillatory nature of the waves. The current model has the potential to be useful for applications related to the metabolic structures that play a vital role in heat sources inside the human body.

New Insight into AuNP Applications in Tumour Treatment and Cosmetics through Wavy Annuli at the Nanoscale.

The purpose of this study is to probe the peristaltic propulsion of a non-Newtonian fluid model with suspended gold nanoparticles. The base fluid is considered to simulate blood using the Carreau fluid model. We model a small annulus as a tube with a peristaltic wave containing a clot propagating towards the tube wall. An external variable magnetic field is also considered in the governing flow. An approximation for long wavelengths and small Reynolds numbers is employed to formulate the governing flow problem. The resulting nonlinear equations are solved using a perturbation scheme. Series solutions are obtained for the velocity profile, temperature profile, pressure rise and streamlines. The results indicate an enhancement in the temperature profile that can be utilized in eradicating tumour cells.

The study of non-Newtonian nanofluid with hall and ion slip effects on peristaltically induced motion in a non-uniform channel.

In this study, we considered the unsteady peristaltic motion of a non-Newtonian nanofluid under the influence of a magnetic field and Hall currents. The simultaneous effects of ion slip and chemical reaction were also taken into consideration. The flow problem was suggested on the basis of the continuity, thermal energy, linear momentum, and nanoparticle concentration, which were further reduced with the help of Ohm's law. Mathematical modelling was executed using the lubrication approach. The resulting highly nonlinear partial differential equations were solved semi-analytically using the homotopy perturbation technique. The impacts of all the pertinent parameters were investigated mathematically and graphically. Numerical calculations have been used to calculate the expressions for the pressure increase and friction forces along the whole length of the channel. The results depict that for a relatively large value of the Brownian parameter, the chemical reaction has a dual behaviour on the concentration profile. Moreover, there is a critical point of the magnetic parameter at which the behaviours of the pressure increase and friction forces are reversed for progressive values of the power law index. The present investigation provides a theoretical model that estimates the impact of a wide range of parameters on the characteristics of blood-like fluid flows.

Particulate suspension effect on peristaltically induced unsteady pulsatile flow in a narrow artery: Blood flow model.

This work is concerned with theoretically investigating the pulsatile flow of a fluid with suspended particles in a flow driven by peristaltic waves that deform the wall of a small blood artery in the shape of traveling sinusoidal waves with constant velocity. The problem formulation in the wave frame of reference is presented and the governing equations are developed up to the second-order in terms of the asymptotic expansion of Womersley number which characterizes the unsteady effect in the wave frame. We suppose that the flow rate imposed, in this frame, is a function versus time. The analytical solution of the problem is achieved using the long wavelength approximation where Reynolds number is considered small with reference to the blood flow in the circulatory system. The present study inspects novelties brought about into the classic peristaltic mechanism by the inclusion of Womersley number, and the critical values of concentration and occlusion on the flow characteristics in a small artery with flexible walls. Momentum and mass equations for the fluid and particle phases are solved by means of a perturbation analysis in which the occlusion is a small parameter. Closed form solutions are obtained for the fluid/particle velocity distributions, stream function, pressure rise, friction force, wall shear stress, instantaneous mechanical efficiency, and time-averaged mechanical efficiency. The physical explanation of the Segré-Silberberg effect is introduced and the trapping phenomenon of plasma for haemodilution and haemoconcentration cases is discussed. It has been deduced that the width of the closed plasma streamlines is increased while their number is minimally reduced in case of haemoconcentration. This mathematical problem has numerous applications in various branches in science including blood flow in small blood vessels. Several results of other models can be deduced as limiting cases of our situation.