122,265 research outputs found
Simplified algorithm for numerical solution of liquid flow equations
No full textKuznetsov V. A. Simplified algorithm for numerical solution of liquid flow equations / V. A. Kuznetsov // Journal of Engineering Physics and Thermophysics. - 2018. - Vol.91, No3. - P. 648-654.An algorithm is suggested for numerical solution of differential equations for velocity and pressure on a staggered grid. The algorithm ensures unconditional convergence of iterations for a correction to pressure and without it
Design of a residual adder in computer systems
No full textThe purpose of this article is to consider an algorithm for synthesizing the structure of the adder of two residuals ai and bi numbers A = (a1, a2,..., ai,..., ak ) and B = (b1, b2,..., bi,..., bk ) for an arbitrary value of the module mi of the residual class system (RCS), by organizing inter-bit connections between binary one-bit adders (BOA), the combination of which makes up the structure of modulo adder. The algorithm for the synthesis of adders by arbitrary modules is based on the usage of existing adders by module M = 2n -1, which consists of a set of sequentially located BOA, by introducing and using additional inter-bit connections of the form X↓i↑ j. Specific examples of the synthesis of structures of binary adders for various values of the RCS modules mi are given
Mathematical Model of the Reliability of a Computer System which is Functioning in the Residual Class System, Taking into Account the Reliability of Switching Devices
No full textThe article discusses the option of constructing of the mathematical model of the reliability of a computer system (CS), which is functioning in the residual class system (RCS). In contrast to the known ones, the proposed mathematical model of reliability, in terms of the probability of failure-free operation, takes into account the influence of the reliability of switching devices on the process of functioning of the CS in the RCS. The results of studies of the proposed mathematical model of the reliability of the CS and the results of the comparative analysis of reliability showed that the use of the RCS provides higher reliability of the CS with lower hardware costs) than the majority tripleting method of the CS, which is widely used in the positional binary notation. This is achieved due to the fact that in the considered version of the mathematical model of the CS reliability, such types of redundancy as: structural, informational and functional, the presence of which is due to the properties of the RNS, are more fully taken into account. This circumstance makes it possible to apply the appropriate backup methods. The article shows that a gain in the amount of CS equipment is achieved from 2.5 to 42%
The Data Control in the System of Residual Classes
No full textThis work discusses issues related to the development and application of methods for improving the efficiency of operation based on the use of the codes of the system of residual classes (SRC). The research is aimed at presents the methods of data operational control in the SRC. The main focus is given to the control methods based on the principle of nullification of numbers in the SRC. It is shown that the resulting redundancy with the introduction of one additional (control) base provides control and correction of errors in the process of performing operations. The algorithms developed and presented in the work allow modeling the data control unit for the practical implementation of the proposed methods. The analysis is performed and the calculated data of the implementation time of the control operation for the considered methods of nullification is obtained, and the conditional amount of the control system equipment is also calculated
Method of Control of Data which is Presented by Residual Classes
No full textThe method of increasing truthfulness of control of data which is presented by residual classes (RC) is considered in the article. The results of calculations and comparative analysis of truthfulness of data control in RC have shown that efficiency of non-positional coding in residual classes greatly rises with bit grid of handled data increasing
Analysis of pattern formation in chaos of coupled bistable elements
No full textOne of the most complex problems of nonlinear dynamics is the investigation of collective dynamics of ensembles consisting of a large number of coupled elements. A number of investigations were carried out for linear coupling of diffusion (difference) type. Recently, based on successful investigations of neurobiological objects [Abarbanel et al., 1996], an interest has grown in the study of dynamics of ensembles with nonlinear, nondiffusion type of coupling. In this paper we address pattern formation in a chain of bistable elements so coupled [Kuznetsov & Shalfeev, 2000]
A new mechanism for buoyancy driven convection in pulsating viscous flows: A theoretical study
No full textA new mechanism for the onset of thermal convection is proposed. This mechanism is the result of the interaction between a pulsating flow, viscous dissipation, and buoyancy within a channel. The study considers a Newtonian fluid moving inside an infinitely wide horizontal channel bounded by impermeable, rigid plates. The basic flow is characterized by a pulsating pressure gradient. Viscous dissipation acts as an internal heat source which produces a potentially unstable basic temperature gradient. The heat source has a vertical non uniform distribution inside the channel. This configuration is investigated with respect to the onset of buoyancy driven convection. The basic state fields are solved analytically by expanding them in series as functions of the pulsating frequency. In order to perform the linear stability analysis, an arbitrarily small perturbation is superimposed upon the basic state order zero solution. The normal mode method is employed and an ordinary differential eigenvalue problem is obtained. The perturbations were found to have zero angular frequency and thus the resonance phenomena between the basic flow and the perturbations can be neglected. The critical values of the governing parameter are obtained by solving the eigenvalue problem numerically. A growth rate analysis of the possibly unstable configurations relative to the most unstable mode is performed. The present study proves, theoretically, that a pulsating flow can undergo thermal convection. A future experimental study is suggested to validate the proposed instability mechanism
A new hydrodynamic boundary condition simulating the effect of rough boundaries on the onset of Rayleigh-Bénard convection
No full textThis paper introduces a new hydrodynamic boundary condition which enables the simulation of the effects caused by rough boundaries. The classical Rayleigh-Bénard stability analysis is performed here to investigate the onset of thermal convection in a parallel-plate channel with rough boundaries. The hydrodynamic boundary conditions are modified, from the classical treatment, in order to consider channel boundaries characterised by non-negligible roughness. This roughness is simulated as a shallow fluid saturated porous medium and the Saffman interface condition is thus employed to model the hydrodynamic boundary conditions. The normal mode method is employed and the obtained eigenvalue problem is solved numerically. The Principle of Exchange of Stabilities is proved and the critical values of the Rayleigh number and of the wave number are obtained
Kuznetsov, Nikolai. Isikuarhiiv
No full text39 säilikutI Käsikirjad, s.1-6. II Teadlaste kirjad N.Kuznetsovile, s.7. III Aukirjad, s.8-18. IV Fotod, s.19-37. V Varia, s.38-39http://www.ester.ee/record=b3526855*es
Asymmetric code-theoretical schemes constructed with the use of algebraic geometric codes
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