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Vol 72, No 1 (2017)

Article

Averaged equations in a Hele-Shaw cell: A stratification model

Logvinov O.A.

Abstract

An averaged model of viscous fluid displacement from a Hele-Shaw cell with consideration of the transverse stratification of flow between the cell plates is proposed.

Moscow University Mechanics Bulletin. 2017;72(1):1-6
pages 1-6 views

A form of the solution to the Mathieu equation

Budanov V.M.

Abstract

A special linear transformation is introduced to express the general solution to a second-order differential equation with a periodic coefficient in terms of a particular solution to an auxiliary second-order nonlinear system with a periodically perturbed right-hand side. It is numerically shown that there exist periodic solutions to the auxiliary system outside the instability regions of the solutions to the Mathieu equation. The estimates obtained for the instability regions are in agreement with known results.

Moscow University Mechanics Bulletin. 2017;72(1):7-12
pages 7-12 views

Stability of a falling conducting liquid film in an alternating electric field

Mogilevskii E.I., Shkadov V.Y.

Abstract

The flow of a thin viscous conducting liquid film falling along one of the plates of a vertically positioned plane capacitor is studied. The capacitor is connected to an alternating current power supply. It is shown that the presence of the electric field leads to flow destabilization; moreover, the parametric resonance of capillary waves is observed.

Moscow University Mechanics Bulletin. 2017;72(1):13-18
pages 13-18 views

Perturbed stable systems on a plane. Part 2

Aleksandrov V.V., Aleksandrova T.B., Konovalenko I.S., Tikhonova K.V.

Abstract

A new transition problem is considered for a stable system with two attractors.

Moscow University Mechanics Bulletin. 2017;72(1):19-22
pages 19-22 views

Effect of the atmospheric electric field under a thundercloud on tornado funnel formation

Maslov S.A.

Abstract

The effect of the atmospheric electric field under a thundercloud on the formation and motion of a tornado funnel is considered. It is shown that the electric force may cause the descent of the developing funnel to the Earth’s surface or its ascent back to the thundercloud.

Moscow University Mechanics Bulletin. 2017;72(1):23-27
pages 23-27 views