Wyniki wyszukiwania - BazTech

1

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

|

2019

|

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.

2

On the effectiveness of variation of physical variables on steady flow between parallel plates with heat transfer in a porous medium

Attia H. A., Abdeen M, A. M.

Journal of Theoretical and Applied Mechanics

|

2013

|

Vol. 51 nr 1

53--61

EN

The effect of variation of physical variables on a steady flow through a porous medium with heat transfer between parallel plates is examined. The viscosity and the thermal conductivity are assumed to be temperature dependent. A constant pressure gradient is applied in the axial direction and the two plates are kept at two constant but different temperatures, while the viscous dissipation is considered in the energy equation. A numerical solution for the governing non-linear coupled equations of motion and the energy equation is determined. The effect of porosity of the medium, the variable viscosity, and the variable thermal conductivity on both the velocity and temperature distributions is reported.

PL

W pracy zbadano wpływ zmiany parametrów fizycznych na ustalony przepływ przez porowaty ośrodek przy jednoczesnym przesyle ciepła pomiędzy równoległymi płytami ograniczającym obszar ośrodka. Założono, że lepkość i współczynnik przewodnictwa cieplnego są zależne od temperatury. Do utrzymania stacjonarnego przepływu wprowadzono stały gradient ciśnienia w kierunku osiowym, a dwie płyty utrzymano w stałych, lecz różniących się temperaturach. Efekt dyssypacji wiskotycznej uwzględniono w równaniu energii. Zaprezentowano numeryczne rozwiązanie nieliniowych, sprzężonych równań ruchu oraz równania energii. Omówiono wpływ porowatości ośrodka, zmiennej lepkości i współczynnika przewodnictwa cieplnego na rozkład prędkości i temperatury w obszarze przepływu.

3

Hall and ion-slip effects on the flow of micropolar fluid between parallel plates

Srinivasacharya D., Shiferaw M.

International Journal of Applied Mechanics and Engineering

|

2008

|

Vol. 13, no 1

251-262

EN

The steady flow of an incompressible and electrically conducting micropolar fluid between two parallel infinite plates is studied taking Hall and ionic effects into consideration. The fluid motion is due to the constant pressure gradient. An extemal uniform magnetic field directed perpendicular to the flow direction is applied. The expressions for the velocity and micro rotation are obtained. The effects of micropolar parameters, magnetic parameter, Hall parameter and ion slip parameter on the velocity, and micro rotation are discussed.

4

Free convection across air gap between corrugated and flat plates

Chowdhury F., Alam S., Akhanda M., Islam A.

Archives of Thermodynamics

|

2002

|

Vol. 23, no 1-2

39-53

EN

Natural convection heat transfer across air gap between a lower hot semicircular corrugated plate and an upper cold flat plate has been studied experimentally for a range of corrugation aspect ratio (air gap to the amplitude of corrugation), 3.5 < A < 9.5, inclination angle, 0^0 < 0 < 45^0, and Rayleigh number, 3.4 x 10^4 Ra < 2.0 x 10^6. A corrugation plate has been formed with the multi-semicircular bars. The heat transfer coefficients are found to be a strong function of corrugation aspect ratio, inclination angle and Rayleigh number. The results are compared with the available information in the literature on natural convection and found to be about 10% and 20% higher than those for a gap between vee corrugated and flat plate and between two flat plates, respectively. Finally, a correlation has been developed for this configuration for a range of parameters studied herein.