Non-axisymmetric Homann stagnation-point flow of unsteady Walter's B nanofluid over a vertical cylindrical disk

Particular non-axisymmetric Homann stagnation point flow of Walter’s B fluid over a vertical cylindrical disk is considered in this work. Important physical aspects of newly transient state problem are described by incorporating the effects of magnetic field and mixed convection. Additionally, the temperature and solute concentration are expressed with new parameters in the form of Brownian motion, thermophoretic force, thermal radiation, and 1st order chemical reaction. Furthermore, the problem is modeled with non-linear PDE’s, and which are further converted into ODE’s along with the proposed geometric conditions. Exploration of new physical impacts are described in the form of velocity, temperature, concentration, and displacement thicknesses by applying numerical scheme. However, the momentum equation subjected to the insufficient boundary conditions converting us to apply perturbation technique to reduce the order of ODE accordingly. It is conducted that displacement thicknesses [Formula: see text] and [Formula: see text] tends to its asymptotic value, as [Formula: see text] On the other hand, the displacement thickness [Formula: see text] is found in reverse trends, for the same escalating values of viscoelastic parameter. The skin friction [Formula: see text] variation against viscoelastic parameter is noticed with uplifting trend when [Formula: see text] and vice versa, for [Formula: see text] Outcomes for the Nusselt and Sherwood numbers and rate of heat and mass transfer have been obtained and discussed for parametric variations of the buoyancy parameter ξ, magnetic parameter M, temperature ratio parameter, Brownian motion parameter [Formula: see text], thermophoresis parameter [Formula: see text] and 1st order chemical reaction Rc. Also, shows relative growth for the momentum and concentration profiles.

Transient Free Convection Mass Transfer of Second-grade Fluid Flow with Wall Transpiration

The study of mass transfer in the non-Newtonian fluid is essential in understanding the engine lubrication, the cooling system of electronic devices, and the manufacturing process of the chemical industry. Optimal performance of the practical applications requires the appropriate conditions. The unsteady transient free convective flow of second-grade fluid with mass transfer and wall transpiration is concerned in the present communication. The behavior of the second-grade fluid under the influence of injection or suction is discussed. Suitable non-dimensional variables are utilized to transform the governing equations into non-dimensional governing equations. A Maple solver “pdsolve” that is using the centered implicit scheme of a finite difference method is utilized to solve the dimensionless governing equations numerically. The effects of wall injection or suction parameter, second-grade fluid viscoelastic parameter, Schmidt number, and modified Grashof number on the velocity and concentration profiles are graphically displayed and analyzed. The results show that with increasing wall suction, viscoelastic parameter, and Schmidt number, the velocity and concentration profiles decrease. Whereas, the velocity profiles show an opposite tendency in situations of wall injection. The wall suction has increased the skin friction and also the rate of mass diffusion in the second-grade fluid.

Seismic wave equation formulated by generalized viscoelasticity in fluid-saturated porous media

Biot’s theory of poroelasticity describes seismic waves propagating through fluid-saturated porous media, so-called two-phase media. The classic Biot’s theory of poroelasticity considers the wave dissipation mechanism being the friction of relative motion between the fluid in the pores and the solid rock skeleton. However, within the seismic frequency band, the friction has a major influence only on the slow P-wave and has an insignificant influence on the fast P-wave. In order to represent the intrinsic viscoelasticity of the solid skeleton, we incorporate a generalized viscoelastic wave equation into Biot’s theory for the fluid-saturated porous media. The generalized equation which unifies the pure elastic and viscoelastic cases is constituted by a single viscoelastic parameter, presented as the fractional order of the wavefield derivative in the compact form of the wave equation. The generalized equation that includes the viscoelasticity appropriately describes the dissipation characteristics of the fast P-wave. Plane-wave analysis and numerical solutions of the proposed wave equation reveal that (1) the viscoelasticity in the solid skeleton causes the energy attenuation on the fast P-wave and the slow P-wave at the same order of magnitude, and (2) the generalized viscoelastic wave equation effectively describes the dissipation effect of the waves propagating through the fluid-saturated porous media.

New modeling and analytical solution of fourth grade (non-Newtonian) fluid by a stretchable magnetized Riga device

The aim of this paper is to examine the influence of heat source/sink on boundary layer flow of a fourth-grade liquid over a stretchable Riga plate on taking account of induced magnetic field and mixed convection. Analysis of mass and heat transport is studied through modified Fourier heat flux model. The governing flow issue is demonstrated with the help of momentum, energy, temperature and concentration equation. The modeled equations are reduced into nondimensional ODEs by opting suitable similarity transformations. The analytic solutions are discussed by means of the optimal technique of homotopy analysis. The influence of several nondimensional parameters on velocity, thermal and concentration gradients are deliberated by using suitable graphs. Also, the skin friction is discussed with the help of graphs. The result outcomes reveal that, velocity of fluid diminishes for advanced values of viscoelastic parameter and fourth-grade liquid parameter but contrary movement is seen for third grade fluid parameters. Fluid temperature boosts up for thermal relaxation parameter and concentration is abridged for rising values of solutal concentration parameter and Schmidt number.

Numerical Investigation at Lower Stagnation Point Flow Over a Horizontal Circular Cylinder of Brinkman-Viscoelastic Fluid

Investigations on the characteristics of fluid flow in manufacturing processes are essential since it will determine the quality of the end products. The flow might be involved whether the Newtonian (viscous) or non-Newtonian fluid moving over the different body depending on the process activities. Since the experimental works sometimes costly and hazardous, the study via mathematical approach is necessary to counter the limitations. Hence, this paper aims to investigate the flow at lower stagnation point over a horizontal circular cylinder on Brinkman Viscoelastic fluid embedded in porous medium. Mathematical model is constructed in terms of partial differential equations with some physical conditions to represent the condition of the problem. An appropriate non-dimensional variable is introduced to transform the model into the solvable system which is in less complexity, and then the system is solved using the Runge-Kutta-Fehlberg method. The numerical solutions for the temperature and velocity profiles as well as skin friction and heat transfer coefficient are computed and presented in graphical and tabular form. The feature of the flow and heat transfer characteristics for various values of mixed convection, Brinkman and viscoelastic parameter are analysed and discussed. This study has found that the incremented Brinkman and viscoelastic parameter have declined the fluid velocity while opposite trend is observed for temperature distribution. The theoretical results produced are relevance to researchers and engineers. It can be used for comparative purposes in data validation or experimentation study.

Numerical investigation fluid velocity and heat transfer on the stretching sheet by VIM method and optimization fluid temperature and velocity parameter by Prandtl number and viscoelastic parameter

This study aimed at investigating the variation of heat transfer and velocity changes of the fluid flow along the vertical line on a surface drawn from both sides. In the beginning, the several parameters such as Prandtl number and viscoelastic effect evaluated for heat transfer and fluid velocity by variation Iteration method. The results were compared with the numerical method. The second part of the description relates to the use RSM method in the Design Expert software. In this paper by using the RSM method, optimized the fluid velocity and heat transfer passing from the stretching sheet. By increasing the Prandtl number, the convection heat transfer 43 % increased ratio the minimum Prandtl number. In accordance with balanced modes for Prandtl number and viscoelastic parameter and wall temperature, the best optimization occurred for fluid velocity and fluid temperature with f=0.67 and θ=0.606. The results of variation iteration method are accurate for the nonlinear solution. As the value of k increases, the value of fluid velocity indicates an increase and by increase Prandtl number, the value of Temperature decreases.

Theoretical analysis of entropy generation in second grade nanofluid considering heat source/sink over a rotating disk

Purpose This study aims to focus on second grade fluid flow over a rotating disk in the presence of chemical reaction. Uniform magnetic field is also taken into account. Because of the smaller magnetic Reynolds number, induced magnetic field is negligible. Heat equation is constructed by considering heat source/sink. Design/methodology/approach Suitable variables are used to transform nonlinear partial differential equations to ordinary ones. Convergent series solutions are attained by applying homotopy analysis method. Findings Trends of different parameters on concentration, velocity and temperature are shown graphically. Skin friction coefficient and local Nusselt number are calculated and investigated under the effect of elaborated parameters. An elevation in the value of magnetic field parameter causes collapse in the velocity distributions. Velocity distribution in increasing function of viscoelastic parameter. Temperature and concentration profiles are decreasing functions of viscoelastic parameter. Concentration distribution reduces by increasing the chemical reaction parameter. There is more surface drag force for larger M, while opposite behavior is noted for β. Originality/value To the best of the authors’ knowledge, such consideration is yet to be published in the literature.

Exploring the nanomechanical concepts of development through recent updates in magnetically guided system

This article outlines an analytical analysis of unsteady mixed bioconvection buoyancy-driven nanofluid thermodynamics and gyrotactic microorganisms motion in the stagnation domain of the impulsively rotating sphere with convective boundary conditions. To make the equations physically realistic, zero mass transfer boundary conditions have been used. The Brownian motion and thermophoresis effects are incorporated in the nanofluid model. Magnetic dipole effect has been implemented. A system of partial differential equations is used to represent thermodynamics and gyrotactic microorganisms motion, which is then transformed into dimensionless ordinary differential equations. The solution methodology is involved by homotopy analysis method. The results obtained are based on the effect of dimensionless parameters on the velocity, temperature, nanoparticles concentration and density of the motile microorganisms profiles. The primary velocity increases as the mixed convection and viscoelastic parameters are increased while it decreases as the buoyancy ratio, ferro-hydrodynamic interaction and rotation parameters are increased. The secondary velocity decreases as viscoelastic parameter increases while it increases as the rotation parameter increases. Temperature is reduced as the Prandtl number and thermophoresis parameter are increased. The nanoparticles concentration is increased as the Brownian motion parameter increases. The motile density of gyrotactic microorganisms increases as the bioconvection Rayleigh number, rotation parameter and thermal Biot number are increased.

Thermal analysis of higher-order chemical reactive viscoelastic nanofluids flow in porous media via stretching surface

The essence of the present investigation is to reveal the hydrothermal variations of viscoelastic nanofluid flow in a porous medium over a stretchable surface. A higher-order chemical reaction is incorporated with thermophoresis and Brownian motion. Similarity conversions reduce the resulting equations into their dimensionless form and then solved using Runge-Kutta-Fehlberg (RKF) based shooting procedure. The effects of underlying factors on the flow are discussed through various graphs and tables. Computational results for noteworthy skin friction and heat and mass transport are presented and reviewed with sensible judgment. The study reveals that the fluid velocity reduces with incremental values of the viscoelastic parameter [Formula: see text] and magnetic strength. The temperature reduces for the suction parameter with the existence of stretchable but enhances with thermophoresis and Brownian motion effects. Heat transfer rate amplifies for [Formula: see text] but declines for [Formula: see text]. Mass transfer rate increases with the increase in Brownian parameter and Schmidt number. A comparative analysis shows a better agreement with previous results in limiting scenarios.

SPECTRAL NUMERICAL STUDY OF ENTROPY GENERATION IN MAGNETO-CONVECTIVE VISCOELASTIC BIOFLUID FLOW THROUGH PORO-ELASTIC MEDIA WITH THERMAL RADIATION AND BUOYANCY EFFECTS

Electromagnetic high-temperature therapy is popular in medical engineering treatments for various diseases include tissue damage ablation repair, hyperthermia and oncological illness diagnosis. The simulation of transport phenomena in such applications requires multi-physical models featuring magnetohydrodynamics, biorheology, heat transfer and deformable porous media. Motivated by investigating the fluid dynamics and thermodynamic optimization of such processes, in the present article a mathematical model is developed to study the combined influence of thermal buoyancy, magnetic field and thermal radiation on the fluid and heat characteristics in electrically-conducting viscoelastic biofluid flow through a vertical deformable porous medium. Jefferys elastic-viscous model is deployed to simulate non-Newtonian characteristics of the biofluid. It is assumed that heat is generated within the fluid by both viscous and Darcy (porous matrix) dissipations. The boundary value problem is normalized with appropriate transformations. The non-dimensional biofluid velocity, solid displacement and temperature equations with appropriate boundary conditions are solved computationally using a spectral method. Verification of accuracy is conducted via monitoring residuals of the solutions and Validated with shooting technique is included. The effects of Jeffrey viscoelastic parameter, viscous drag parameter, magnetic field parameter, radiation parameter and buoyancy parameter on flow velocity, solid displacement, temperature and entropy generation are depicted graphically and interpreted at length. Increasing magnetic field and drag parameters are found to reduce the field velocity, solid displacement, temperature and entropy production. Higher magnitudes of thermal radiation parameter retard the flow and decrease Nusselt number whereas they elevate solid displacement.