scholarly journals A Numerical Study of MHD Carreau Nanofluid Flow with Gyrotactic Microorganisms over a Plate, Wedge, and Stagnation Point

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
R. M. Akram Muntazir ◽  
M. Mushtaq ◽  
K. Jabeen
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Brownian Motion ◽  
Flat Plate ◽  
Friction Factor ◽  
Stagnation Point ◽  
Shear Thickening ◽  
Shear Thinning ◽  
Gyrotactic Microorganisms ◽  
Carreau Nanofluid

This article addresses the numerical exploration of steady and 2D flow of MHD Carreau nanofluid filled with motile microorganisms over three different geometries, i.e., plate, wedge, and stagnation point of a flat plate. The influence of magnetic field, viscous dissipation, thermophoresis, and Brownian motion is considered for both cases, i.e., shear thinning and shear thickening. A set of relevant similarity transformations are utilized to obtain dimensionless form of governing coupled nonlinear partial differential equations (PDEs). The transformed system of ordinary differential equations (ODEs) is then numerically solved by bvp4c via MATLAB based on shooting technique and Runge–Kutta–Fehlberg (RKF) scheme via MAPLE. Also, a numerical analysis has been made for skin friction factor, heat, and mass transfer rates. Results elucidate that all the profiles except velocity show decreasing behavior for higher values of magnetic field parameter. Among all three flow geometries for both shear thinning and shear thickening cases, the flow over a plate has lesser skin friction factor. The nanoparticle concentration and density of motile microorganism decrease in both the shear thinning and shear thickening cases, for increasing values of Brownian motion (Nb), but reverse trend is observed for rising values of thermophoresis parameter (Nt). Furthermore, it is observed that, as we increase the values of suction/injection parameter (S), the velocity of fluid increases but decreases the fluid temperature, concentration of mass and density of motile organisms over a plate, wedge, and stagnation point of a flat plate. Also, we observed that shear thinning nanofluid has higher rate of heat, mass, and motile microorganisms mass transfers than shear thickening fluid. Both shear thinning and thickening nanofluid have a low rate of heat/mass and gyrotactic microorganisms mass transfer over plate among wedge and stagnation point flow.

MHD free convection flow in an inclined square cavity filled with both nanofluids and gyrotactic microorganisms

2019 ◽  
Vol 29 (12) ◽  
pp. 4642-4659 ◽  
Author(s):  
Mikhail Sheremet ◽  
Teodor Grosan ◽  
Ioan Pop
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Free Convection ◽  
Hartmann Number ◽  
Convection Flow ◽  
Square Cavity ◽  
Free Convection Flow ◽  
Gyrotactic Microorganisms ◽  
Content Type ◽  
Field Inclination

Purpose This paper aims to study the magnetohydrodynamic (MHD)-free convection flow in an inclined square cavity filled with both nanofluids and gyrotactic microorganism. Design/methodology/approach The benefits of adding motile microorganisms to the suspension include enhanced mass transfer, microscale mixing and anticipated improved stability of the nanofluid. The model includes equations expressing conservation of total mass, momentum, thermal energy, nanoparticles, microorganisms and oxygen. Physical mechanisms responsible for the slip velocity between the nanoparticles and the base fluid, such as Brownian motion and thermophoresis, are accounted for in the model. Findings It has been found that the Hartmann number suppresses the heat and mass transfer, while the cavity and magnetic field inclination angles characterize a non-monotonic behavior of the all considered parameters. A rise of the Hartmann number leads to a reduction of the influence rate of the magnetic field inclination angle. Originality/value The present results are original and new for the study of MHD-free convection flow in an inclined square cavity filled with both nanofluids and gyrotactic microorganisms.

Mass transfer between a plane surface and an impinging turbulent jet: the influence of surface-pressure fluctuations

1982 ◽  
Vol 119 ◽  
pp. 91-105 ◽  
Author(s):  
K. Kataoka ◽  
Y. Kamiyama ◽  
S. Hashimoto ◽  
T. Komai
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Flat Plate ◽  
Stagnation Point ◽  
Surface Pressure ◽  
Velocity Gradient ◽  
Large Scale ◽  
Pressure Fluctuations ◽  
Wall Region ◽  
Local Measurement

Local measurement of the mass-transfer rate and velocity gradient when an axisymmetric jet impinges on a flat plate was carried out using an electrochemical technique. Local measurement of the surface pressure on the flat plate was carried out separately using piezoelectric pressure transducers. The stagnation-point mass-transfer coefficient reaches a maximum when the flat plate is placed at 6 nozzle diameters from a convergent nozzle. It has been confirmed that the mass transfer to the flat plate for a high Schmidt number is greatly enhanced owing to the velocity-gradient disturbances in the wall region of the boundary layer, while the momentum transfer is insensitive to such disturbances. The relative intensity of the velocity-gradient fluctuations on the wall has an extremely large value at and near to the stagnation point, and decreases downstream, approaching a large constant value.These velocity-gradient disturbances are not due to the usual interaction of Reynolds stress with the shear stress of the mean flow, but are due to the interaction with the surface-pressure fluctuations converted from the velocity fluctuations of the oncoming jet.The three co-ordinate dimensions of large-scale eddies are calculated from the auto- and spatial correlations of the surface-pressure fluctuations. It is considered that such large-scale eddies play an important role in the production of a velocity-gradient disturbance in the wall region of the boundary layer from the velocity turbulence of the approaching jet.

Unsteady convective heat and mass transfer of a nanofluid in Howarth’s stagnation point by Buongiorno’s model

2015 ◽  
Vol 25 (5) ◽  
pp. 1176-1197 ◽  
Author(s):  
Saeed Dinarvand ◽  
Reza Hosseini ◽  
Ioan Pop
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Stagnation Point Flow ◽  
Content Type ◽  
Buongiorno’S Model ◽  
Brownian Motion And Thermophoresis

Purpose – The purpose of this paper is to do a comprehensive study on the unsteady general three-dimensional stagnation-point flow and heat transfer of a nanofluid by Buongiorno’s model. Design/methodology/approach – In this study, the convective transport equations include the effects of Brownian motion and thermophoresis. By introducing new similarity transformations for velocity, temperature and nanoparticle volume fraction, the basic equations governing the flow, heat and mass transfer are reduced into highly non-linear ordinary differential equations. The resulting non-linear system has been solved both analytically and numerically. Findings – The analysis shows that velocity, temperature and nanoparticle concentration profiles in the respective boundary layers depend on five parameters, namely unsteadiness parameter A, Brownian motion parameter Nb, thermophoresis parameter Nt, Prandtl number Pr and Lewis number Le. It is found that the thermal boundary layer thickens with a rise in both of the Brownian motion and the thermophoresis effects. Therefore, similar to the earlier reported results, the Nusselt number decreases as the Brownian motion and thermophoresis effects become stronger. A correlation for the Nusselt number has been developed based on a regression analysis of the data. This correlation predicts the numerical results with a maximum error of 9 percent for a usual domain of the physical parameters. Originality/value – The stagnation point flow toward a wavy cylinder (with nodal and saddle stagnation points) that a little attention has been given to it up to now. The examination of unsteadiness effect on the general three-dimensional stagnation-point flow. The application of an interesting and global model (Boungiorno’s model) for the nanofluid that incorporates the effects of Brownian motion and thermophoresis. The study of the effects of Brownian motion and thermophoresis on the nanofluid flow, heat and mass transfer characteristics. The prediction of correlation for the Nusselt number based on a regression analysis of the data. General speaking, we can tell the problem with this geometry, characteristics, the applied model, and comprehensive results, was Not studied and analyzed in literature up to now.

scholarly journals Stagnation Point Flow of Nanofluid over a Moving Plate with Convective Boundary Condition and Magnetohydrodynamics

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fazle Mabood ◽  
Nopparat Pochai ◽  
Stanford Shateyi
Keyword(s):  
Mass Transfer ◽  
Differential Equations ◽  
Friction Factor ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Volume Fraction ◽  
Convective Boundary Condition ◽  
Stagnation Point Flow ◽  
Moving Plate ◽  
Convective Boundary

A theoretical investigation is carried out to examine the effects of volume fraction of nanoparticles, suction/injection, and convective heat and mass transfer parameters on MHD stagnation point flow of water-based nanofluids (Cu and Ag). The governing partial differential equations for the fluid flow, temperature, and concentration are reduced to a system of nonlinear ordinary differential equations. The derived similarity equations and corresponding boundary conditions are solved numerically using Runge-Kutta Fehlberg fourth-fifth order method. To exhibit the effect of the controlling parameters on the dimensionless velocity, temperature, nanoparticle volume fraction, skin friction factor, and local Nusselt and local Sherwood numbers, numerical results are presented in graphical and tabular forms. It is found that the friction factor and heat and mass transfer rates increase with magnetic field and suction/injection parameters.

scholarly journals Mathematical analysis for Brownian motion of nonlinear thermal bioconvective stagnation point flow in a nanofluid using DTM and RKF method

2020 ◽  
Vol 7 (3) ◽  
pp. 294-307
Author(s):  
Surya Kanta Mondal ◽  
Dulal Pal
Keyword(s):  
Mass Transfer ◽  
Brownian Motion ◽  
Differential Equations ◽  
Stagnation Point ◽  
Nonlinear Differential Equations ◽  
Transformation Method ◽  
Stagnation Point Flow ◽  
Transform Method ◽  
Differential Transform ◽  
Nonlinearly Stretching Sheet

Abstract In the present paper, bioconvective stagnation point flow of nanofluid containing gyrotactic microorganisms over a nonlinearly stretching sheet embedded in a porous medium is considered. The scaling group transformation method is introduced to obtain the similarity transformation to convert the governing partial differential equations to a set of ordinary differential equations. The reduced governing nonlinear differential equations are then solved numerically with Runge–Kutta–Fehlberg method. Differential transform method is employed to justify the results obtained by the numerical method. It is found that both the results matched nicely. It is noticed that the density of motile microorganism distribution grows high with an increase in the values of the bioconvection Peclet number. Further, the rate of heat transfer and the rate of mass transfer increase rapidly with an increment in the thermophoresis parameter, heat source parameter, chemical reaction parameter, and Brownian motion parameter, respectively. This work is relevant to engineering and biotechnological applications, such as in the design of bioconjugates and mass transfer enhancement of microfluidics.

Double Diffusive Convection in Flow Couple Stress Nanofluid in a Permeable Wall Vertical Channel in the Presence of a Magnetic Field

2019 ◽  
Vol 26 ◽  
pp. 30-44
Author(s):  
Noureddine Messaoudi ◽  
Mohamed Nadjib Bouaziz ◽  
Hamza Ali Agha
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Brownian Motion ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Couple Stress ◽  
Volume Fraction ◽  
Nonlinear Partial Differential Equations ◽  
Vertical Channel ◽  
Strong Impact

In this work, the flow of a couple stress nanofluid in a vertical channel with heat and mass transfer in the presence of a magnetic field and taking account the Brownian motion, the thermophoresis as well as the effect of Soret and Dufour was simulated numerically using Matlab following the code bvp4c. The nonlinear partial differential equations governing this particular flow are transformed into a system of ordinary differential equations via the similarity technique. The influence of the parameters describing the behavior of the problem studied on the velocity, temperature, concentration and volume fraction fields of the nanoparticles, as well as on the coefficient of friction, Nusselt and Sherwood numbers, were highlighted for the end of the study. understand their effect on heat and mass transfer. The rheology of the nanofluid and the magnetic field have a strong impact on the velocity and temperature profiles, while the parameters of Brownian motion and thermophoresis promote heat transfer.

scholarly journals Magnetohydrodynamic Boundary Layer Flow of Nanofluid over an Exponentially Stretching Permeable Sheet

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Krishnendu Bhattacharyya ◽  
G. C. Layek
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Brownian Motion ◽  
Volume Fraction ◽  
Lewis Number ◽  
Nanoparticle Volume Fraction ◽  
Layer Flow ◽  
Wall Mass

A mathematical model of the steady boundary layer flow of nanofluid due to an exponentially permeable stretching sheet with external magnetic field is presented. In the model, the effects of Brownian motion and thermophoresis on heat transfer and nanoparticle volume friction are considered. Using shooting technique with fourth-order Runge-Kutta method the transformed equations are solved. The study reveals that the governing parameters, namely, the magnetic parameter, the wall mass transfer parameter, the Prandtl number, the Lewis number, Brownian motion parameter, and thermophoresis parameter, have major effects on the flow field, the heat transfer, and the nanoparticle volume fraction. The magnetic field makes enhancement in temperature and nanoparticle volume fraction, whereas the wall mass transfer through the porous sheet causes reduction of both. For the Brownian motion, the temperature increases and the nanoparticle volume fraction decreases. Heat transfer rate becomes low with increase of Lewis number. For thermophoresis effect, the thermal boundary layer thickness becomes larger.

Effects of hydromagnetic and chemical reaction over a stagnation point flow of horizontal stretching/shrinking cylinder in Ag-CuO/water hybrid nanofluid

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nur Adilah Liyana Aladdin ◽  
Norfifah Bachok
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Mass Transfer ◽  
Skin Friction ◽  
Stagnation Point ◽  
Chemical Reaction ◽  
Transfer Rate ◽  
Stagnation Point Flow ◽  
Hybrid Nanofluid ◽  
Content Type

Purpose This paper aims to explore on stagnation point flow of Ag-CuO/water over a horizontal stretching/shrinking cylinder by adding the effect of chemical reaction, B together with the magnetic field, M. Design/methodology/approach A set of reduced ordinary differential equations from the governing equations of partial differential equations is obtained through similarities requirements. The resulting equations are solved using bvp4c in MATLAB2019a. The impact of various physical parameters such as curvature parameter, ϒ, chemical reaction rate, B, magnetic field, M and Schmidt numbers, Sc on shear stress, f′′0 local heat flux, -θ′(0) and mass transfer, -∅′(0) also for velocity, f′(η), temperature, θ(η) and concentration, ∅(η) profiles have been plotted and briefly discussed. In this work, some vital characteristics such as local skin friction, Cf, local Nusselt number, Nux and local Sherwood number, Shx are chosen for physical and numerical analysis. Findings The findings expose that the duality of solutions appears in a shrinking region ( ε < 0). The value of skin friction, heat transfer rate and mass transfer rate reduction for existing of M, but in contrary result obtain for larger ϒ, B and Sc. Furthermore, the hybrid nanofluid demonstrates better heat transfer compared to nanofluid. Practical implications The hybrid nanofluid has widened its applications such as in electronic cooling, manufacturing, automotive, heat exchanger, solar energy, heat pipes and biomedical, as their efficiency in the heat transfer field is better compared to nanofluid. Originality/value The findings on stagnation point flow of Ag-CuO/water over a horizontal stretching/shrinking cylinder with the effect of chemical reaction, B and magnetic field, M is new and the originality is preserved for the benefits of future researchers.

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