Abstracts of papers for

Previous issue vol. 47, no. 3 (2006)

vol. 47, no. 4 (2006)

Contents of issue 4, vol. 47

1. T. Zyss, A. Stanisławczyk, B. Sawicki: Location of electrodes for recording the EEG signal: selected problems
2. M.A.M. Al Khatib: The squeezing flow problem of Herschel-Bulkley fluids in a closing a wedge
3. K. Piela, A. Teodorczyk: Numerical simulation of detonation with adaptive grid
4. R.C. Chaudhary, Preeti Jain: Influence of fluctuating surface temperature and velocity on unsteady MHD natural convection adjacent to a permeable surface immersed in porous medium with heat absorption

T. Zyss, A. Stanisławczyk, B. Sawicki: Location of electrodes for recording the EEG signal: selected problems

The paper deals with problems connected with location of electrodes for recording the EEG signal in standard and enhanced system. A procedure of taking measurements on the head has been presented. The authors indicate the necessity of applying precise spatial coordinates of electrodes in scientific research.

Contents

M.A.M. Al Khatib: The squeezing flow problem of Herschel-Bulkley fluids in a closing a wedge

The non-steady squeezing flow of a Herschel-Bulkley fluid in a two-dimensional wedge is investigated. The problem is reduced to a nonlinear two-point boundary-value problem. An exact similarity solution is obtained without any geometrical approximation. The velocity and stress fields are calculated for Herschel-Bulkley fluids and for power-law and Bingham fluids as special cases. The location of the yielded and unyielded regions is determined. The results for the power-law fluids are compared with the approximate analytical solution obtained by Chen [15].

Key words: squeezing wedge flow, Herschel-Bulkley fluid, two-point boundary-value problem.

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K. Piela, A. Teodorczyk: Numerical simulation of detonation with adaptive grid

In this paper we report the results of numerical simulation of the detailed structure of detonation. We have used a Flux-Corrected Transport (FCT) algorithm that can reproduce discontinuities with small dispersion errors and minimal numerical diffusion. Such algorithm makes it possible to do 2D calculations at reasonable cost in computer time and memory. The objective of our work was to demonstrate the capabilities of the adaptive grid (Adaptive Mesh Refinement Method) which enabled massive savings in computing time. The second objective was to simulate formation of the structure of 2D detonation wave.

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R.C. Chaudhary, Preeti Jain: Influence of fluctuating surface temperature and velocity on unsteady MHD natural convection adjacent to a permeable surface immersed in porous medium with heat absorption

The present study will focus on the combined effect of oscillating surface temperature and fluctuating surface velocity, under the action of uniform transverse magnetic field applied normally to the plane and internal heat absorption effect. The wall temperature is oscillating periodically in time about a non-zero constant mean temperature. The plate is permeable enabling possible fluid withdrawal. The nonlinear coupled partial differential equations governing the flow, representing the constitutive laws, are transformed into a system of ordinary differential equations by the perturbation technique. A parametric study of all the parameters involved is conducted and a representative set of numerical results concerning the velocity and temperature profiles, as well as the amplitude and phase of skin friction and Nusselt number, is illustrated graphically to show typical trends of the solutions.

Key words: natural convection, hydromagnetics, heat transfer, sinks.

Contents