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1
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On the Nonlinear Effects of Magnetoacoustic Perturbations in a Perfectly Conducting Viscous and Thermoconducting Gas

100%
Perelomova A.
Acta Physica Polonica A
|
2016
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vol. 130
|
issue 3
727-733
EN
Nonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. The plasma is assumed to be a Newtonian thermoconducting gas with infinite electrical conductivity permeated by a magnetic field orthogonal to the trajectories of gas particles. Generation of the non-wave modes (magnetoacoustic heating and streaming) in the field of periodic and aperiodic magnetoacoustic perturbations is discussed. The results are compared with acoustic heating and streaming in an nonmagnetized Newtonian gas. In contrast with a Newtonian gas, the magnetoacoustic forces of heating and streaming are not proportional to the summary attenuation. The magnetoacoutic force of streaming is always smaller than the Newtonian one, but that of heating may take larger or smaller value in dependence on the magnetic strength.
2
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Interaction of Acoustic and Thermal Modes in the Vibrationally Relaxing Gases. Acoustic Cooling

100%
Perelomova A.
|
EN
The dynamic equation which governs an excess temperature associated with the thermal mode in vibrationally relaxing gas is derived. The nonlinear transfer of acoustic energy to the energy of the thermal mode in a relaxing gas causes slow variation of temperature with time. The final dynamic equation is instantaneous. All types of sound, including aperiodic, may be considered as an acoustic source of corresponding heating or cooling. The study considers sound with frequencies much larger than the inverse time of the thermodynamic relaxation. In the nonequilibrium regime, if standard attenuation is neglected, gas temperature decreases with time. Examples concern heating and cooling caused by periodic in time sound and an impulse. The influence of standard viscosity, thermal conductivity, and heat withdrawal is briefly discussed.
3
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On the Nonlinear Effects of Magnetoacoustic Perturbations in Optically Thin Quasi-Isentropic Plasmas

63%
Perelomova A., Ratkowski F.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 1
194-200
EN
Nonlinear effects of planar magnetosound perturbations in a plasma are discussed. Plasma is non-adiabatic due to optically thin radiation and external heating. For these reasons, thermal instability of a plasma may appear which makes it acoustically active. The plasma is assumed to be initially homogeneous ideal gas with infinite electrical conductivity permeated by a straight magnetic field which is orthogonal to the trajectories of gas particles. The instantaneous dynamic equations which describe nonlinear effects of intense sound in quasi-isentropic plasma, are derived. Nonlinear interaction of periodic and aperiodic magnetoacoustic perturbations with the non-wave modes, are discussed. The conclusions concern dissipative or active behavior of magnetoacoustic perturbations which is determined by the kind of the heating-cooling function.
4
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Acoustic Streaming Induced by Periodic and Aperiodic Sound in a Bubbly Liquid

63%
Wojda P., Perelomova A.
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|
vol. 125
|
issue 5
1138-1143
EN
The vortex flow which follows intense sound propagating in a bubbly liquid, is considered. The reasons for acoustic streaming are both nonlinearity and dispersion. That makes streaming especial as compared with that in a Newtonian fluid. Conclusions concern the vortex flow induced in a half-space by initially harmonic or impulse Gaussian beam. The vortex flow recalls a turbulent flow with increasing in time number of small-scale vortices in the vicinity of the axis of a beam's propagation.
5
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Non-Wave Variations in Temperature Caused by Sound in a Chemically Reacting Gas

63%
Perelomova A., Pelc-Garska W.
Acta Physica Polonica A
|
2011
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vol. 120
|
issue 3
455-461
EN
A weakly nonlinear generation of non-acoustic modes in the field of sound in a gas is considered. An exoteric chemical reaction of A → B type, which takes place in a gas, may be reversible or not. Two types of sound are considered, low-frequency and high-frequency as compared with the characteristic time of a chemical reaction. For both these cases, the governing equations of non-acoustic modes are derived and conclusions of the efficiency of their nonlinear generation by sound are made. The character of nonlinear generation of non-acoustic modes by sound depends essentially on reversibility of a chemical reaction.
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