Wyniki wyszukiwania - BazTech

1

Span-wise fluctuating MHD convective flow of a viscoelastic fluid through a porous medium in a hot vertical channel with thermal radiation

Singh K. D.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 3

667--681

EN

An unsteady mixed convection flow of a visco-elastic, incompressible and electrically conducting fluid in a hot vertical channel is analyzed. The vertical channel is filled with a porous medium. The temperature of one of the channel plates is considered to be fluctuating span-wise cosinusoidally, i.e., [...]. A magnetic field of uniform strength is applied perpendicular to the planes of the plates. The magnetic Reynolds number is assumed very small so that the induced magnetic field is neglected. It is also assumed that the conducting fluid is gray, absorbing/emitting radiation and non-scattering. Governing equations are solved exactly for the velocity and the temperature fields. The effects of various flow parameters on the velocity, temperature and the skin friction and the Nusselt number in terms of their amplitudes and phase angles are discussed with the help of figures.

2

MHD flow and heat transfer of a micropolar fluid over a stretchable disk

Ashraf M., Batool K.

Journal of Theoretical and Applied Mechanics

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2013

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Vol. 51 nr 1

25--38

EN

A numerical study of an axisymmetric steady laminar incompressible flow of an electrically conducting micropolar fluid over a stretchable disk is carried out when the fluid is subjected to an external transverse magnetic field. The governing nonlinear equations of motion are transformed into a dimensionless form through Von Karman’s logic similarity functions. An algorithm based on a finite difference scheme is used to solve the reduced coupled nonlinear ordinary differential equations with the associated boundary conditions. Effects of the micropolar parameters, the magnetic parameter and the Prandtl number on the flow velocity and temperature distribution are discussed. Investigations predict that the heat transfer rate at the surface of the disk increases with an increase in the values of micropolar parameters. The magnetic field enhances the shear and couple stresses. The shear stress factor is lower for micropolar fluids as compared to Newtonian fluids, which may be beneficial in flow and heat control of polymeric processing.

PL

W pracy zaprezentowano wyniki badań numerycznych nad osiowo-symetrycznym, laminarnym i ustalonym opływem elektrycznie przewodzącej cieczy mikropolarnej wokół rozciągliwego dysku przy jednoczesnym oświetleniu cieczy polem magnetycznym. Nieliniowe równanie ruchu opływu sprowadzono do postaci bezwymiarowej za pomocą funkcji podobieństwa von Karmana. Do rozwiązania uproszczonych, sprzężonych i nieliniowych równań różniczkowych zwyczajnych z towarzyszącymi warunkami brzegowymi użyto algorytmu opartego na metodzie różnic skończonych. Przedyskutowano wpływ parametrów mikropolarności, wartości pola magnetycznego oraz liczby Prandtla na rozkład prędkości i temperatury cieczy. Według badań, tempo przepływu ciepła na powierzchni dysku wzrasta z rosnącymi wartościami parametrów mikropolarności. Dodatkowo, obecność pola magnetycznego powiększa naprężenia ścinające i momentowe. Wartość naprężeń ścinających jest mimo to mniejsza dla cieczy mikropolarnej niż dla newtonowskiej, co może być korzystne w monitorowaniu przepływu i transferu ciepła podczas procesu obróbki polimerów.

3

Reflection Coefficient and Non-WKB Effects for Alfvén Waves Propagating in the Solar Wind

Krogulec M., Musielak Z. E.

Acta Astronomica

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1998

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Vol. 48, No. 1

77--90

EN

The propagation of Alfvén waves in spherically symmetric, isothermal solar wind models with two different temperatures T0=2.85×106 K and T0=8.2×105 K is considered. The steady-state Alfvén wave equations are solved numerically and the resulting reflection coefficient and non-WKB effects are calculated. The obtained results show that the reflection coefficient is practically zero in the high-temperature wind model, where wave reflection and non-WKB effects are essentially absent, and that it can also be zero in the low-temperature model, where wave reflection and non-WKB effects are present. A physical explanation of these results is given.