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1
Content available Analysis of factors affecting destabilization of a viscous liquid flow in channels
Mamedov Asiman, Hnativ Roman, Yakhno Oleg, Murashchenko Alena
International Journal of Applied Mechanics and Engineering
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2023
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Vol. 28, no. 3
86--100
EN
An analysis of the influence of inertia forces and ponderomotive forces on the destabilization of the flow of viscous fluids in the hydrodynamic initial section is given. Cases of flow of viscous, anomalously viscous and electrically conductive liquids are considered; the degree of influence of mass forces on the destabilization of the flow is estimated. As applied to the flow in the hydrodynamic initial section, the degree of influence of inertia forces from convective acceleration and forces with a magnetic nature can be different. Inertia forces stimulate the accelerated movement of the fluid, and in the case of forces with a magnetic nature, ponderomotive forces contribute to deceleration, which is confirmed by the results of studies of the velocity field. Recommendations are given for calculating the length of the hydrodynamic initial section in the presence of mass forces with different nature.
2
Content available Numerical solution of MHD channel flow in a porous medium with uniform suction and injection in the presence of an inclined magnetic field
Chutia Muhim
Journal of Applied Mathematics and Computational Mechanics
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2022
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Vol. 21, nr 2
5--13
EN
In this paper, the steady fully developed MHD flow of a viscous incompressible electrically conducting fluid through a channel filled with a porous medium and bounded by two infinite walls is investigated numerically for the cases (i) Poiseuille flow and (ii) Couette-Poiseuille flow; with uniform suction and injection at the walls in the presence of an inclined magnetic field. The Brinkman equation is used for the flow in the porous channel and solved numerically using the finite difference method. Numerical results are obtained for velocity. The effects of various dimensionless parameters such as Hartmann number (M), suction/injection parameter (S), permeability parameter (α) and angle of inclination (θ) on the flow are discussed and presented graphically.
3
Content available remote Effect of magnetic and temperature variation on Al2O3 nanofluid convection
Chawla Meenu, Bhardwaj Rashmi, Bangia Aashima, Das Saureesh, Goncerzewicz Jan
Mathematica Applicanda
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2020
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Vol. 48, no. 1
3--23
EN
Nonlinear dynamics of Aluminium Oxide (Al2O3) nanofluid convection under variation of the external magnetic field and temperature variation is studied using a system of partial differential equations arising from equations of conservation of momentum and energy. Applying Galerkin approximation the system of first-order ordinary differential equations is obtained. In the above system, by stability analysis, a critical condition for stability is obtained which is verified through numerical simulations. The influence of variation of magnetic field and temperature is examined through variation of Hartmann number Ha and Rayleigh number Ra As Ra increases, the system enters into a chaotic phase which can be transformed into a stable state of convection by the increase of the external magnetic field. Thus, the external magnetic field is useful in controlling the undesired chaotic state of nanofluid convection. The present study is significant in applications as nanofluids are used in medical treatment, coolants in nuclear reactors and engines, environmental engineering, industrial engineering, and many other applications in the industries.
PL
Artykuł poświęcony jest nieliniowej dynamice tlenku glinu (Al2O3). Konwekcja nanocieczy w warunkach zmienności zewnętrznego pola magnetycznego i zmian temperatury jest badana za pomocą układu równań różniczkowych cząstkowych wynikających z równań zachowania pędu i energia. Stosując przybliżenie Galerkina uzyskuje się układ równań różniczkowych zwyczajnych pierwszego rzędu. W powyższym systemie, za pomocą analizy stateczności, uzyskuje się krytyczny warunek stateczności, który jest weryfikowany za pomocą symulacji numerycznych. Wpływ zmienności pola magnetycznego i temperatury bada się na podstawie zmiany liczby Hartmanna Ha i liczby Rayleigha Ra. Wraz ze wzrostem Ra układ wchodzi w fazę chaotyczną, która może zostać przekształcona w stabilny stan konwekcji poprzez wzrost zewnętrznego pola magnetycznego. Zatem zewnętrzne pole magnetyczne jest przydatne w kontrolowaniu niepożądanego chaotycznego stanu konwekcji nanofluidu. Niniejsze badanie ma istotne znaczenie w zastosowaniach, ponieważ nanociecze są wykorzystywane w leczeniu, chłodziwach w reaktorach jądrowych i silnikach, inżynierii środowiska, inżynierii przemysłowej i wielu innych zastosowaniach przemysłowych.
4
Content available Role of sudden application or withdrawal of magnetic field on MHD Couette flow
Jha B. K., Oni M. O.
International Journal of Applied Mechanics and Engineering
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2019
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Vol. 24, no. 4
92--105
EN
This article investigates the impact of a sudden application or sudden withdrawal of a magnetic field on an unsteady MHD Couette flow formation in a parallel plate channel. The governing momentum equation is derived and solved exactly in Laplace domain using the Laplace transform technique with the necessary initial and boundary conditions to capture the present physical situation for the cases; sudden application or sudden withdrawal of a magnetic field. Due to the complexity of the solution obtained, the Riemann-sum approximation technique is used to transform the Laplace domain to time domain. During the course of graphical and tabular representations, results show that the Hartmann number, time and nature of application of a magnetic field play an important role in the transition from hydrodynamic to magnetohydrodynamic flow and vice-versa. Also, fluid velocity steady-state solution is independent on whether the magnetic field is fixed relative to the moving plate or to the fluid for sudden withdrawal of magnetic field. In addition, the application of a sudden magnetic field leads to a delay in the attainment of steady-state solution.
5
Content available Entropy analysis of third-grade MHD convection flows from a horizontal cylinder with slip
Madhavi K., Prasad V. R., Gaffar S. A., Venkatadri K.
Archive of Mechanical Engineering
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2018
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Vol. LXV, nr 3
417--440
EN
In thermos fluid dynamics, free convection flows external to different geometries, such as cylinders, ellipses, spheres, curved walls, wavy plates, cones, etc., play major role in various industrial and process engineering systems. The thermal buoyancy force associated with natural convection flows can play a critical role in determining skin friction and heat transfer rates at the boundary. In thermal engineering, natural convection flows from cylindrical bodies has gained exceptional interest. In this article, we mathematically evaluate an entropy analysis of magnetohydrodynamic third-grade convection flows from permeable cylinder considering velocity and thermal slip effects. The resulting non-linear coupled partial differential conservation equations with associated boundary conditions are solved with an efficient unconditionally stable implicit finite difference Keller-Box technique. The impacts of momentum and heat transport coefficients, entropy generation and Bejan number are computed for several values of non-dimensional parameters arising in the flow equations. Streamlines are plotted to analyze the heat transport process in a two-dimensional domain. Furthermore, the deviations of the flow variables are compared with those computed for a Newtonian fluid and this has important implications in industrial thermal material processing operations, aviation technology, different enterprises, energy systems and thermal enhancement of industrial flow processes.
6
Content available remote Simultaneous effects of thermal radiation and chemical reaction on hydromagnetic pulsatile flow of a Casson fluid in a porous space
Kumar C. K., Srinivas S.
Engineering Transactions
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2017
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Vol. 65, iss. 3
461--481
EN
In the present study, the hydromagnetic pulsating flow of Casson fluid between two parallel plates in a porous space, thermal radiation and chemical reaction are investigated. The analytical solutions for flow variables are obtained by using a perturbation technique. The effects of pertinent parameters on velocity, temperature, concentration, Nusselt number and Sherwood number distributions are studied in detail.
7
Content available Hall effects on MHD flow past an accelerated plate with heat transfer
Sundarnath J. K., Muthucumarswamy R.
International Journal of Applied Mechanics and Engineering
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2015
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Vol. 20, no. 1
171--181
EN
Hall current and rotation on an MHD flow past an accelerated horizontal plate relative to a rotating fluid, In the presence of heat transfer has been analyzed. The effects of the Hall parameter, Hartmann number, rotation parameter (non-dimensional angular velocity), Grashof’s number and Prandtl number on axial and transverse velocity profiles are presented graphically. It is found that with the increase in the Hartmann number, the axial and transverse velocity components increase in a direction opposite to that of obtained by increasing the Hall parameter and rotation parameter. Also, when […], it is observed that the transverse velocity component vanishes and axial velocity attains a maximum value.
8
Content available Unsteady hydromagnetic Couette flow due to ramped motion of one of the porous plates
Jha B. K., Jibril H. M.
International Journal of Applied Mechanics and Engineering
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2013
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Vol. 18, no. 4
1039--1056
EN
An unsteady flow formation in Couette motion of an electrically conducting fluid subject to transverse magnetic field has been analyzed in the presence of suction/injection through the porous plates when one of the porous plates is in ramped motion. It is assumed that the porous plates are uniformly permeable and the fluid is entering the flow region through one of the porous plates at same rate as it is leaving through the other porous plate. The resulting boundary value problem has been solved exactly under the assumption of a negligible induced magnetic field, external electric field and pressure gradient. Unified closed form expressions for the velocity field and skin-friction corresponding to the case of a magnetic field fixed relative to the fluid or to the moving porous plate have been presented. In order to highlight the impact of the ramp motion of the porous plate on the fluid flow, it has also been compared with Couette flow between porous plates when one of the porous plates has been set into an impulsive motion.
9
Content available remote Study of an oxygenation process in capillary in the presence of magnetic field
Bali R., Awasthi U., Sharma S. K.
International Journal of Applied Mechanics and Engineering
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2011
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Vol. 16, no 2
331-344
EN
A mathematical model for the transport of oxygen in the systemic capillaries and the surrounding tissue in the presence of a magnetic field is presented in this paper. We have modeled the capillary by a circular cylinder surrounded by a tissue of uniform thickness. The model takes into account the transport mechanisms of molecular diffusion, convection and diffusion due to the presence of hemoglobin as a carrier of the gases (oxygen).The resulting system of differential equations is solved analytically by the method of separation of variable and Picard's method. The result for partial pressure of oxygen in the capillary and tissue region is obtained. The effect of the Hartmann number (H) and others parameters is obtained and discussed through graphs.
10
Content available remote Hall effects on oscillatory Couette flow
Ghara N., Maji S. L., Das S., Jana R. N.
International Journal of Applied Mechanics and Engineering
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2011
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Vol. 16, no 4
1005-1020
EN
Hall effects on the oscillatory Couette flow between two horizontal parallel plates are studied. One of the plate is at rest and the other one oscillates in its own plane. The effects of Hall and frequency parameters on the velocities and the shear stresses for the steady and unsteady flows are analyzed. It is found that the shear stresses at the M stationary plate due to the unsteady primary and secondary velocities have a phase lag over the plate oscillations for those values of the Hall parameter m, Hartmann number and the frequency parameter , we have considered.
11
Content available remote On pulsatile hydromagnetic flow of an oldroyd fluid with heat transfer
Srinivas S., Malathy T., Sachdev P. L.
Engineering Transactions
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2007
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Vol. 55, iss. 1
79-94
EN
The problem of heat transfer to pulsatile flow of hydromagnetic viscoelastic fluid has been studied. Expressions for the velocity, temperature distribution and mass flow rate are obtained. The rate of heat transfer at the plates has also been calculated. These expressions are evaluated numerically for various values of the parameters. The influence of pertinent parameters on temperature, heat transfer coefficient and mass flux has been studied and numerical results obtained are presented graphically.
12
Magnetohydrodynamic fully developed combined convection flow between vertical plates heated asymmetrically
Ghosh S., Nandi D.
Journal of Technical Physics
|
2000
|
Vol. 41, no 2
173-185
EN
Magnetohydrodynamic (MHD) fully developed flow of a viscous incompressible electrically conducting fluid in a vertical channel during combined convection, with asymmetric heating of the wall, under the influence of a constant pressure gradient and in the presence of an uniform transverse magnetic field, is studied. Exact solution of the governing equation is obtained in a closed form. The solution in dimensionless form contains two pertinent flow parameters, viz. M (the Hartmann number) and Gr(the Grashof number). The limiting cases of a MHD forced and free convection are analyses, what has not beem done earlier in the literature. The occurrence of flow reversal indicates that there arises a flow reversal at the cold wall when r[sub T] = 1 while, for r[sub T] < 1, no flow reversal is possible in the absence of magnetic forces.
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