Effects Of Pertinent Flow Parameters Research Articles

Numerical simulation and regression analysis of MHD dissipative and radiative flow of a Casson nanofluid with Hall effects

The magnetohydrodynamic (MHD) flow of Casson nanofluid has several applications in engineering and medical processes. The present research work is performed to examine the unsteady viscous dissipative and radiative flow of a Casson nanofluid over a stretching sheet under the influence of a transverse magnetic field with a view to highlight the impact of Hall current. The mathematical model comprising of nonlinear coupled PDE is transformed into a set of coupled ODEs using appropriate similarity transformation. The reduced mathematical model in a similar form is then solved by adopting the successive linearization method (SLM). The residual analysis is used to validate the solutions. A parametric study is performed to inquire about the impacts of Hall current, nonlinear thermal radiation, viscous dissipation, and other pertinent flow parameters such as temperature ratio, Brownian movement, thermophoresis on the nanofluid velocities, temperature, and concentration. The effects of pertinent flow parameters are also examined on the skin-friction coefficients, Nusselt number, and Sherwood number. A quadratic regression analysis is presented to estimate the skin-friction coefficient and Nusselt number for different values of effecting parameters. Results reveal that the increasing values of Casson parameter decrease the fluid velocity and temperature, whereas a converse trend is detected in concentration profile, rate of heat transfer and mass transfer.

The paradox of heat conduction, influence of variable viscosity, and thermal conductivity on magnetized dissipative Casson fluid with stratification models

The boundary layer flow of temperature-dependent variable thermal conductivity and dynamic viscosity on flow, heat, and mass transfer of magnetized and dissipative Casson fluid over a slenderized stretching sheet has been studied. The model explores the Cattaneo-Christov heat flux paradox instead of the Fourier’s law plus the stratifications impact. The variable temperature-dependent plastic dynamic viscosity and thermal conductivity were assumed to vary as a linear function of temperature. The governing systems of equations in PDEs were transformed into non-linear ordinary differential equations using the suitable similarity transformations, hence the approximate solutions were obtained using Chebyshev Spectral Collocation Method (CSCM). Effects of pertinent flow parameters on concentration, temperature, and velocity profiles are presented graphically and tabled, therein, thermal relaxation and wall thickness parameters slow down the distribution of the flowing fluid. A rise in Casson parameter, temperature-dependent thermal conductivity, and velocity power index parameter increases the skin friction thus leading to a decrease in energy and mass gradient at the wall, also, temperature gradient attain maximum within 0.2 - 1.0 variation of Casson parameter.

Entropy generation and dissipative heat transfer analysis of mixed convective hydromagnetic flow of a Casson nanofluid with thermal radiation and Hall current

The present article provides a detailed analysis of entropy generation on the unsteady three-dimensional incompressible and electrically conducting magnetohydrodynamic flow of a Casson nanofluid under the influence of mixed convection, radiation, viscous dissipation, Brownian motion, Ohmic heating, thermophoresis and heat generation. At first, similarity transformation is used to transform the governing nonlinear coupled partial differential equations into nonlinear coupled ordinary differential equations, and then the resulting highly nonlinear coupled ordinary differential equations are numerically solved by the utilization of spectral quasi-linearization method. Moreover, the effects of pertinent flow parameters on velocity distribution, temperature distribution, concentration distribution, entropy generation and Bejan number are depicted prominently through various graphs and tables. It can be analyzed from the graphs that the Casson parameter acts as an assisting parameter towards the temperature distribution in the absence of viscous and Joule dissipations, while it has an adverse effect on temperature under the impacts of viscous and Joule dissipations. On the contrary, entropy generation increases significantly for larger Brinkman number, diffusive variable and concentration ratio parameter, whereas the reverse effects of these parameters on Bejan number are examined. Apart from this, the numerical values of some physical quantities such as skin friction coefficients in x and z directions, local Nusselt number and Sherwood number for the variation of the values of pertinent parameters are displayed in tabular forms. A quadratic multiple regression analysis for these physical quantities has also been carried out to improve the present model’s effectiveness in various industrial and engineering areas. Furthermore, an appropriate agreement is obtained on comparing the present results with previously published results.

On dual solutions of the unsteady MHD flow on a stretchable rotating disk with heat transfer and a linear temporal stability analysis

The present paper is an extension of the work done by Fang and Tao (2012) in the presence of a magnetic field. The external magnetic field is applied normal to a stretchable disk surface and heat is transferred from the disk surface to the ambient fluid which gives a new family of unsteady viscous flow over a stretchable rotating disk with deceleration. The Navier–Stokes equations and the energy equation admit similarity solutions depending on unsteadiness parameter. The resulting set of highly nonlinear ordinary differential equations are solved numerically. Two solution branches are found due to the effect of unsteadiness parameter for several values of magnetic parameter and stretching parameter. The effects of pertinent flow parameters on the shear stresses on radial and tangential directions, Nusselt numbers, torque, dimensionless velocity and temperature profiles are shown graphically for both the solution branches and their physical interpretation are discussed in detail. Emphasis has been laid to check the stability of dual solution branches. The stability is tested by the sign of the smallest eigenvalue, and our analysis reveals that the lower solution branches are unstable.

Magnetohydrodynamic stagnation point on a Casson nanofluid flow over a radially stretching sheet.

This article proposes a numerical model to investigate the impact of the radiation effects in the presence of heat generation/absorption and magnetic field on the magnetohydrodynamics (MHD) stagnation point flow over a radially stretching sheet using a Casson nanofluid. The nonlinear partial differential equations (PDEs) describing the proposed flow problem are reduced to a set of ordinary differential equations (ODEs) via suitable similarity transformations. The shooting technique and the Adams–Moulton method of fourth order are used to obtain the numerical results via the computational program language FORTRAN. Nanoparticles have unique thermal and electrical properties which can improve heat transfer in nanofluids. The effects of pertinent flow parameters on the nondimensional velocity, temperature and concentration profiles are presented. Overall, the results show that the heat transfer rate increases for higher values of the radiation parameter in a Casson nanofluid.

Hydromagnetic Oscillatory Slip Flow of a Visco-elastic Fluid through a Porous Channel

An investigation is carried out to study the effects of suction/injection on the slip flow of oscillatory visco-elastic hydromagnetic flow through a vertical porous channel. It is considered that the fluid has small electrical conductivity and the electro-magnetic force produced is also very small. The flow is subjected to suction at the cold wall and injection at the heated wall. Under the Boussinesq’s approximation, the governing equations are solved using multiparameter perturbation technique. The effects of pertinent flow parameters on fluid velocity, temperature, shearing stress, the rate of heat transfer is obtained and illustrated graphically. This study plays an important role in physiological, industrial and hydrological problems under suitable conditions.

MHD free convective heat transfer in a Walter’s liquid-B fluid past a convectively heated stretching sheet with partial wall slip

The prime aim of the present investigation is to capture the mechanism of Navier’s velocity slip and convective thermal boundary condition on the flow of MHD viscoelastic fluid over a stretching surface. Additionally, the analysis also includes the effect of natural convection and thermal radiation. The governing boundary layer equations are transformed into a set of highly non-linear ordinary differential equations using suitable similarity transforms. Galerkin Finite element method is used to solve this boundary value problem. Effects of pertinent flow parameters on the Skin friction coefficient, Nusselt number, velocity and temperature, are described graphically. Numerical results obtained in this paper are compared with earlier published results and are found to be in excellent agreement. Significant findings of the present article are the conjugate effect of partial velocity slip and viscoelasticity of the fluid on Skin friction, Nusselt number, velocity and temperature. The analysis shows that presence of partial velocity slip changes the behavior of Nusselt number and skin friction coefficients significantly in comparison to the no slip condition. The present problem has potential to serve as a model for many industrial processes such as cooling and/or drying of paper and textile, rolling sheet drawn from a die, manufacturing of polymeric sheets, sheet glass and crystalline materials, etc.

Effects of Rotation, Radiation and Hall Current on MHD Flow of A Viscoelastic Fluid Past an Infinite Vertical Porous Plate through Porous Medium with Heat Absorption, Chemical Reaction and Variable Suction

The present study analyses the effects of Hall current and heat absorption on a viscous, incompressible, optically thick and electrically conducting viscoelastic fluid flow past an infinite vertical porous plate through porous medium in rotating system with variable suction, thermal radiation and chemical reaction in the presence of uniform magnetic field. The perturbation technique is employed to solve the governing nonlinear partial differential equations to obtain the expressions for velocity, temperature and concentration profile. With the help of graphs and tables, the effects of pertinent flow parameters on the velocity, temperature and concentration fields, shear stress, Nusselt number and Sherwood number within the boundary layer are discussed. The results reveal that the observed parameters in rotating system have a noteworthy influence on the ow, heat and mass transfer.

Magnetohydrodynamic squeezing flow of casson nanofluid between two parallel plates in a porous medium using method of matched asymptotic expansion

In this paper, unsteady squeezing flow of Casson nanofluid between two parallel plates embedded in a porous medium and subjected to magnetic field is analyzed. The developed systems of partial differential equations for the fluid flow models are converted to ordinary differential equations through suitable similarity variables. The obtained ordinary differential equation is solved using method of matched asymptotic expansion. The accuracies of the approximate analytical method for the small and large values of squeezing numbers are investigated. Good agreements are established between the results of the approximate analytical method and the results numerical method using fourth-fifth order Runge-Kutta-Fehlberg method. Thereafter, the developed approximate analytical solutions are used to investigate the effects of pertinent flow parameters on the squeezing flow phenomena of the nanofluids between the two moving parallel plates. The results established that the as the squeezing number and magnetic field parameters decreases, the flow velocity increases when the plates come together. Also, the velocity of the nanofluids further decreases as the magnetic field parameter increases when the plates move apart. However, the velocity is found to be directly proportional to the nanoparticle concentration during the squeezing flow i.e. when the plates are coming together and an inverse variation between the velocity and nanoparticle concentration is recorded when the plates are moving apart. It is hope that this study will enhance the understanding the phenomena of squeezing flow in various applications.

Effects of chemical reaction and heat absorption on hydromagnetic flow past a moving plate through porous medium with ramped wall temperature in the presence of Hall current and thermal radiation

This paper deals with the study of effects of chemical reaction and heat absorption on an unsteady free convective flow of a viscous, incompressible, electrically conducting and optically thin fluid past an infinite vertical moving plate through porous medium with ramped wall temperature in the presence of Hall current and thermal radiation. The governing equations are converted into non-dimensional form and then solved by using the Laplace transform technique. The expressions are obtained for fluid velocity, fluid temperature, species concentration, skin friction, Nusselt number and Sherwood numbers. Effects of pertinent flow parameters are presented graphically and discussed quantitatively. It is found that the increase in chemical reaction and heat absorption parameters contribute in thinning the momentum and thermal boundary layers.

Heat transfer enhancement in hydromagnetic dissipative flow past a moving wedge suspended by H2O-aluminum alloy nanoparticles in the presence of thermal radiation

This letter investigates the two dimensional magnetohydrodynamic Falkner Skan flow of water saturated with AA7072–H2O and AA7075–H2O nanoparticles over a moving wedge. Influence of viscous dissipation and thermal radiation is also under consideration. The model is reduced into nondimensional form by using defined self-similar transformations. Then, numerical study (Runge-Kutta numerical scheme) is carried out for solution purpose. The effects of pertinent flow parameters are discussed in the flow regimes by means of graphical aid. Graphical results for special cases (static wedge and when the movement of flow and wedge is in opposite direction) of the model are also elucidated graphically. It is noted that fluid velocity decreases for volumetric fraction and magnetic force favor the velocity. Significant effects of thermal radiation and nanoparticles volume fraction pointed for thermal filed and the influence of Eckert number is almost inconsequential. For more radiative fluid heat transfer coefficient decreases and nanoparticles volumetric fraction favor the local rate of heat transfer. In the presence of AA7075 nanoparticles, rate of heat transfer is quite rapid as compared to that of AA7072 nanoparticles. To validate the present computations, some present results are compared with already existing results in the literature and found better agreement between them. Finally, major points of the study ingrained in the last section of the letter.

Analysis of hydromagnetic natural convection radiative flow of a viscoelastic nanofluid over a stretching sheet with Soret and Dufour effects

PurposeThe purpose of this paper is to assess steady, two-dimensional natural convection flow of a viscoelastic, incompressible, electrically conducting and optically thick heat-radiating nanofluid over a linearly stretching sheet in the presence of uniform transverse magnetic field taking Dufour and Soret effects into account.Design/methodology/approachThe governing boundary layer equations are transformed into a set of highly non-linear ordinary differential equations using suitable similarity transforms. Finite element method is used to solve this boundary value problem. Effects of pertinent flow parameters on the velocity, temperature, solutal concentration and nanoparticle concentration are described graphically. Also, effects of pertinent flow parameters on the shear stress, rate of heat transfer, rate of solutal concentration and rate of nanoparticle concentration at the sheet are discussed with the help of numerical values presented in graphical form. All numerical results for mono-diffusive nanofluid are compared with those of double-diffusive nanofluid.FindingsNumerical results obtained in this paper are compared with earlier published results and are found to be in excellent agreement. Viscoelasticity, magnetic field and nanoparticle buoyancy parameter tend to enhance the wall velocity gradient, whereas thermal buoyancy force has a reverse effect on it. Radiation, Brownian and thermophoretic diffusions tend to reduce wall temperature gradient, whereas viscoelasticity has a reverse effect on it. Nanofluid Lewis number tends to enhance wall nanoparticle concentration gradient.Originality/valueStudy of this problem may find applications in engineering and biomedical sciences,e.g. in cooling and process industries and in cancer therapy.

Unsteady Hydromagnetic Flow of a Heat Absorbing Dusty Fluid Past a Permeable Vertical Plate with Ramped Temperature

The unsteady flow and heat transfer of a viscous incompressible, electrically conducting dusty fluid past vertical plate under the influence of a transverse magnetic field is studied with a view to examine the combined effects of suction, heat absorption and ramped wall temperature. The temperature of the wall is assumed to have a temporarily ramped profile which goes on increasing up to a certain time limit and then becomes constant. To investigate the effect of rampedness in wall temperature, the solution for the flow past an isothermal wall is also obtained. The governing partial differential equations are solved using Laplace transformation technique in which the inversion is obtained numerically using Matlab. To validate the results of numerical inversion a comparison between the numerical and analytical values of fluid and particle temperatures and Nusselt number is also presented. The effects of pertinent flow parameters affecting the flow and heat transfer are investigated with the help of graphs and tables. It is found that the increase in suction, heat absorption and particle concentration contribute in thinning the thermal and momentum boundary layers and the velocity and temperature for both the fluid and particle phases are higher in the case of a flow past an isothermal plate than that of a flow past a plate with ramped temperature.

FREE CONVECTION FLOW OF A SECOND-GRADE FLUID WITH RAMPED WALL TEMPERATURE

In this paper, exact solutions for free convection flow of a second-grade fluid with ramped wall temperature are obtained using the Laplace transform technique. The effects of pertinent flow parameters on velocity and skin friction are studied with the aid of various graphs. It is found that with an increasing second-grade parameter, the fluid velocity decreases for both ramped and isothermal wall temperatures and the skin friction increases. However, the magnitude of velocity in the case of the ramped temperature is quite smaller than the isothermal temperature for increasing values of the second-grade parameter.

MHD Peristaltic Transport of a Jeffery Fluid in a Channel With Compliant Walls and Porous Space

Here an attempt has been made to investigate the magnetohydrodynamic (MHD) flow of a non-Newtonian fluid filling the porous space in a channel with compliant walls. Constitutive equations of a Jeffery fluid are used in the mathematical modeling. The flow is created due to sinusoidal traveling waves on the channel walls. The resulting problem is solved analytically and series solution for a stream function is derived. The effects of pertinent flow parameters are discussed through graphs.