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According to theory, fluctuations with a power spectrum inversely proportional to frequency (1/f processes) may arise when dissimilar phase transitions simultaneously take place in physical systems with intense white noise. In this work, relaxation effects in establishing a steady-state stochastic process with non-equilibrium phase transitions are described in terms of two nonlinear stochastic differential equations. The results thus obtained carry information on the statistics of large-scale low-frequency spikes. Step “forgetting” of initial conditions is noted. It is numerically shown that the distributions of the durations and maximal values of extreme low-frequency spikes have a power-type form. 相似文献
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V. N. Skokov V. P. Koverda A. V. Reshetnikov 《Journal of Experimental and Theoretical Physics》2001,92(3):535-541
The results are given of an experimental investigation of fluctuation phenomena under conditions of electric arc discharge. Fluctuations are observed whose spectral density is inversely proportional to frequency (1/f noise). Power dependences are revealed of the fluctuation distribution functions. The behavior of spectral density and of distribution functions is associated with the simultaneous occurrence of various nonequilibrium phase transitions. Within the framework of the mean field theory, a mathematical model is suggested of interacting nonequilibrium phase transitions in a distributed system, which predicts the self-organization of the critical state and the generation of fluctuations with diverging spectral characteristics. An adequate agreement is observed between the suggested model and experimental data. 相似文献
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Journal of Applied Mechanics and Technical Physics - A system of two nonlinear stochastic equations is used to simulate fluctuations near a critical transition. Their interaction results... 相似文献
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A. N. Pavlenko V. P. Koverda A. V. Reshetnikov A. S. Surtaev A. N. Tsoi N. A. Mazheiko K. A. Busov V. N. Skokov 《Journal of Engineering Thermophysics》2013,22(3):174-193
This paper represents results on investigating the dynamics of boiling and disintegration of superheated liquid films and jets. The first part deals with experimental study of boiling liquid outflow through short cylindrical and slit channels. Evolution of disintegration of a hot water jet flow is observed both at low and moderate superheating and at high and limit superheating, and also for vaporization mechanisms corresponding to these superheatings. Peculiarities of disintegration of jets through slit and cylindrical channels are noticed. Results on measuring the reactive thrust of the jet through a slit channel under different geometrical conditions behind the channel outlet are represented. The 1/f fluctuations in transient regimes of superheated liquid boiling and in transient regimes of behavior of the jet shape are found. The second part of this article represents results on experimental investigation of nonsteady heat transfer and dynamics of the development of crisis phenomena at boiling of a falling subcooled liquid film in the conditions of stepwise heat release. The experimental data were obtained using synchronized high-speed infrared thermography and video. It is shown that with growth and condensation of vapor bubbles, on the liquid film interface appear large-amplitude waves that lead to considerably increasing local intensity of heat transfer. New data on the boiling incipience temperature in a subcooled liquid film, depending on the heat flux density, are obtained. It is found that the development of boiling crisis is a result of appearance of local dry patches and their subsequent growth by the mechanism of longitudinal thermal conductivity in the heat transfer wall as the equilibrium heat flux density is exceeded. 相似文献
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The stability of the resultant process, which appears upon the interaction of a random process having a 1/f spectrum with a deterministic action, is analyzed using the entropy maximum principle. Under the action of a harmonic force, stable resultant processes are divided into two branches depending on the amplitude of the harmonic force. Due to an exponential relaxation upon an increase in the damping coefficient, the resultant process acquires the Lorentz spectrum without high-energy low-frequency spikes. 相似文献
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V. P. Koverda V. N. Skokov V. P. Skripov 《Journal of Experimental and Theoretical Physics》1998,86(5):953-958
The results of an experimental investigation of a high-power source of broad-band 1/f noise, which can be generated in a system of two interacting nonequilibrium phase transitions, are presented. This process
takes place when a normal conductor-superconductor phase transition is superposed on the critical liquid-vapor transition
in a boiling coolant. A mathematical model describing a nonequilibrium phase transition in a complicated nonlinear system
with two interacting order parameters, which involves the conversion of white noise into stochastic fluctuations of the order
parameters with 1/f and 1/f
2 spectra, is proposed. The properties of the model fluctuations with a 1/f spectrum agree qualitatively with the experimentally observed properties. A characteristic difference between the model fluctuations
with a 1/f
2 spectrum and random walks is also noted.
Zh. éksp. Teor. Fiz. 113, 1748–1757 (May 1998) 相似文献
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A. V. Reshetnikov V. I. Sannikov V. N. Skokov V. P. Koverda 《Journal of Applied Mechanics and Technical Physics》2007,48(1):7-10
Arc current fluctuations between a solid metal electrode and a liquid melt of alkaline carbonates at atmospheric pressure
are measured. Arc current fluctuation power spectra are determined from the measurement data. It is shown that the fluctuation
power is inversely proportional to the frequency (1/f-fluctuations). The fluctuations have a normal Gaussian distribution.
The observed 1/f fluctuations exhibit scale invariance.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 1, pp. 11–15, January–February, 2007. 相似文献
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Extreme fluctuations are modeled by a point system of stochastic equations, in which power spectra inversely proportional to the frequency are produced under the effect of white noise. The distribution of extreme fluctuations corresponds to the maximum of statistical entropy, which points to their stability in nature. By calculating the spectral entropy of random processes, it becomes possible to investigate their stability directly from power spectra without the need to calculate the amplitude distribution functions. The spectral entropy as a function of white noise amplitude has a minimum. The position of the spectral entropy minimum corresponds to the critical state of the system in which the spectra of fluctuating quantities are inversely proportional to the frequency. 相似文献