Hybrid nanofluid flow towards an elastic surface with tantalum and nickel nanoparticles, under the influence of an induced magnetic field

Author(s):  
Lijun Zhang ◽  
M. M. Bhatti ◽  
Efstathios E. Michaelides ◽  
M. Marin ◽  
R. Ellahi
2019 ◽  
Vol 30 (3) ◽  
pp. 1345-1364 ◽  
Author(s):  
Mohamad Mustaqim Junoh ◽  
Fadzilah Md Ali ◽  
Norihan Md Arifin ◽  
Norfifah Bachok ◽  
Ioan Pop

Purpose The purpose of this paper is to investigate the steady magnetohydrodynamics (MHD) boundary layer stagnation-point flow of an incompressible, viscous and electrically conducting fluid past a stretching/shrinking sheet with the effect of induced magnetic field. Design/methodology/approach The governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations via the similarity transformations before they are solved numerically using the “bvp4c” function in MATLAB. Findings It is found that there exist non-unique solutions, namely, dual solutions for a certain range of the stretching/shrinking parameters. The results from the stability analysis showed that the first solution (upper branch) is stable and valid physically, while the second solution (lower branch) is unstable. Practical implications This problem is important in the heat transfer field such as electronic cooling, engine cooling, generator cooling, welding, nuclear system cooling, lubrication, thermal storage, solar heating, cooling and heating in buildings, biomedical, drug reduction, heat pipe, space aircrafts and ships with better efficiency than that of nanofluids applicability. The results obtained are very useful for researchers to determine which solution is physically stable, whereby, mathematically more than one solution exist. Originality/value The present results are new and original for the problem of MHD stagnation-point flow over a stretching/shrinking sheet in a hybrid nanofluid, with the effect of induced magnetic field.


2021 ◽  
Vol 11 (4) ◽  
pp. 1722
Author(s):  
Nidal Abu-Libdeh ◽  
Fares Redouane ◽  
Abderrahmane Aissa ◽  
Fateh Mebarek-Oudina ◽  
Ahmad Almuhtady ◽  
...  

In this study, a new cavity form filled under a constant magnetic field by Ag/MgO/H2O nanofluids and porous media consistent with natural convection and total entropy is examined. The nanofluid flow is considered to be laminar and incompressible, while the advection inertia effect in the porous layer is taken into account by adopting the Darcy–Forchheimer model. The problem is explained in the dimensionless form of the governing equations and solved by the finite element method. The results of the values of Darcy (Da), Hartmann (Ha) and Rayleigh (Ra) numbers, porosity (εp), and the properties of solid volume fraction (ϕ) and flow fields were studied. The findings show that with each improvement in the Ha number, the heat transfer rate becomes more limited, and thus the magnetic field can be used as an outstanding heat transfer controller.


Author(s):  
Riya Ghosh ◽  
Titilayo M. Agbaje ◽  
Sabyasachi Mondal ◽  
Sachin Shaw

Bio-convection is an important phenomenon which is described by hydrodynamic instability and pattern in suspension of biased swimming microorganisms. This hydrodynamics instability arises due to the coupling force between the motion of the micoorganisms and fluid flow. It becomes more significant when nanoparticles are immersed in the base fluid with non-Newtonian rheology. This study presents the bio-convection for a viscoelastic Casson nanofluid flow over a stretching sheet. The Cattaneo–Christov double diffusion, induced magnetic field, thermal radiation, heat generation, viscous dissipation and chemical reaction are taken into account. The boundary condition is enriched with the suction / injection and melting phenomena at the surface. Highly coupled nonlinear governing equations are simplified into a system of coupled ordinary differential equation by using proper similarity transformation. The spectral quasi-linearization method (SQLM) is used to solve the transformed governing equations numerically. Good agreement is observed with the numerical data investigated in the previous outstanding works. It is observed that the density of the motile microorganisms depends on Peclet number and bio-convective Lewis number. Bio-convection Rayleigh number increases the possibility of bio-convection in the system which results in the enhancement of temperature. It is also examined that temperature and concentration profiles increase with the Eckert number and thermophoresis parameter.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Iskandar Waini ◽  
Anuar Ishak ◽  
Ioan Pop ◽  
Roslinda Nazar

Purpose This paper aims to examine the Cu-Al2O3/water hybrid nanofluid flow over a shrinking sheet in the presence of the magnetic field and dust particles. Design/methodology/approach The governing partial differential equations for the two-phase flow of the hybrid nanofluid and the dust particles are reduced to ordinary differential equations using a similarity transformation. Then, these equations are solved using bvp4c in MATLAB software. The bvp4c solver is a finite-difference code that implements the three-stage Lobatto IIIa formula. The numerical results are gained for several values of the physical parameters. The effects of these parameters on the flow and the thermal characteristics of the hybrid nanofluid and the dust particles are analyzed and discussed. Later, the temporal stability analysis is used to determine the stability of the dual solutions obtained as time evolves. Findings The outcome shows that the flow is unlikely to exist unless satisfactory suction strength is imposed on the shrinking sheet. Besides, the heat transfer rate on the shrinking sheet decreases with the increase of . However, the increase in and lead to enhance the heat transfer rate. Two solutions are found, where the domain of the solutions is expanded with the rising of, and. Consequently, the boundary layer separation on the surface is delayed in the presence of these parameters. Implementing the temporal stability analysis, it is found that only one of the solutions is stable as time evolves. Originality/value The dusty fluid problem has been widely studied for the flow over a stretching sheet, but only limited findings can be found for the shrinking counterpart. Therefore, this study considers the problem of the dusty fluid flow over a shrinking sheet containing Cu-Al2O3/water hybrid nanofluid with the effect of the magnetic field. In fact, this is the first study to discover the dual solutions of the dusty hybrid nanofluid flow over a shrinking sheet. Also, further analysis shows that only one of the solutions is stable as time evolves.


2020 ◽  
Vol 10 (8) ◽  
pp. 3001-3009 ◽  
Author(s):  
Tanzila Hayat ◽  
W. A. Khan ◽  
S. Z. Abbas ◽  
S. Nadeem ◽  
S. Ahmad

2019 ◽  
Vol 139 (3) ◽  
pp. 2119-2127 ◽  
Author(s):  
K. Ganesh Kumar ◽  
H. J. Lokesh ◽  
Sabir A. Shehzad ◽  
Tehmina Ambreen

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