Wyniki wyszukiwania - Biblioteka Nauki

1

The effect of magnetic field and compressibility on the Rayleigh - Taylor instability

100%

Vijayalakshmi A. R.

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tom Vol. 16, no 3

899-910

EN

The Rayleigh-Taylor instability of inviscid electrically conducting compressible fluid layer of finite thickness in the presence of magnetic field has been investigated. The linear growth rate for the instability that occurs when the density in the region above the interface is greater than that of fluid below is calculated by solving the linear eigenvalue problem obtained using the normal mode analysis. This problem has been solved separately in both the regions which are filled with constant temperature ideal polytrope exponentially stratified electrically conducting fluids and the eigenfrequencies are obtained by using the kinematic and dynamic pressure matching conditions at the interface. Thus we have obtained the solution of the eigenvalue problem for the frequencies and investigated its dependence on the wave number k and other parameters. We have also obtained various limiting cases viz when the wave number k - 0 and the adiabatic index [...]. For finite y i.e., compressible fluids, it is observed that the growth rates are greater than that for the incompressible fluids. It is also observed that the growth rate decreases with magnetic field. Numerical results are obtained and the limiting cases are deduced which illustrate the importance of the general nature of the problem and the conclusions.

2

Heat and mass transfer effects on rotating fluid past a moving vertical plate in the presence of radiation

100%

Vijayalakshmi A. R.

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2012

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tom Vol. 17, no. 1

299-307

EN

Thermal radiation effects on an unsteady free convection and mass transfer over a moving vertical plate in a rotating fluid are considered theoretically. An exact solution is obtained for the axial and transverse components of the velocity by defining complex velocity. The effects of velocity, temperature and concentration for different parameters such as radiation parameter, rotation parameter, Schmidt number, thermal Grashof number, mass Grashof number, Prandtl number and time on the plate are discussed.

3

MHD and chemical reaction on flow past an impulsively started semi-infinite vertical plate with thermal radiation

63%

Muthucumaraswamy R. , Vijayalakshmi A. R.

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tom Vol. 15, no 1

161-174

EN

A finite difference solution of MHD and thermal radiation effects on unsteady flow past an impulsively started semi-infinite vertical plate in the presence of homogeneous chemical reaction of first order have been studied. The dimensionless governing equations are solved by an efficient, more accurate, unconditionally stable and fast converging implicit finite difference scheme. The effects of velocity and temperature for different parameters such as the chemical reaction parameter, magnetic field parameter, radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time are studied. It is observed that velocity decreases with increasing values of the magnetic field parameter or radiation parameter. It is also observed that due to the presence of first order chemical reaction, velocity increases during generative reaction and decreases in destructive reaction.

4

The evolution of linearized perturbations in a magnetohydrodynamic boundary layer

63%

Vijayalakshmi A. R. , Balagondar P. M.

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tom Vol. 19, no. 2

397--406

EN

The evolution of linearized perturbations in a magnetohydrodynamic shear flow is studied using the initial value problem approach. Here the resulting equation in time posed by using the Fourier transform is solved for the Fourier amplitudes for modeled boundary layer for different initial disturbances. The shear flow prototype here is a piecewise linear approximation of a magnetohydrodynamic boundary layer. The initial disturbances that are considered are a point source of the field of transverse velocity and magnetic field. Solutions are obtained for small values of Alfve’n velocity. The velocity plots are drawn for different values of Alfve’n velocity.

5

The evolution of three-dimensional perturbations in a magnetohydrodynamic couette flow

63%

Balagondar P. M. , Vijayalakshmi A. R.

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2008

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tom Vol. 13, no 3

627-638

EN

The evolution of three-dimensional disturbances in a magnetohydrodynamic Couette flow is investigated using the initial-value problem approach. The general solution to the linearized equations governing three-dimensional disturbances is obtained by using two-dimensional Fourier transformation and other transformations rather than the traditional normal mode approach. The governing stability equation is solved using both the Fourier method and perturbation method. In the Fourier approach, the stability equation is reduced to Mathieu's equation and a periodic solution is obtained. Perturbation solution is obtained for small values of Alfvén velocity. Here Green's function method is employed to obtain the time evolution of linearized disturbances. A measure of disturbance energy is obtained in the case of square wave pulse for velocity and the magnetic field. The time evolution of the three-dimensional disturbances is obtained in terms of the two Green's function representations, one in the form of a Fourier sine series and the other in the form of sine hyperbolic functions representing the energy of a single component and the total energy of a single component. It is shown graphically that the total energy and the sum of first five components of energy are similar but are of different magnitudes.