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Direct Numerical Simulation of Two-Dimensional Turbulence and Investigation of the Boundary Conditions Influence on the Energy Cascade Formation 22nd

Direct Numerical Simulation of Two-Dimensional Turbulence an...

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22nd International Conference on Computational Mechanics and Modern Applied Software Systems, CMMASS 2021

作者： Denisenko, Vladimir V. Fortova, Svetlana V. Institute of Computer Aided Design of the Russian Academy of Sciences 19/18 Vtoraya Brestskaya ul. Moscow123056 Russia

ISBN: (纸本)9789811689253

We consider a two-dimensional turbulence in a finite cell excited by a periodic external force (pumping) with a wavelength of the order of the cell size L. In the case the direct enstrophy cascade is formed. In the absence of bottom friction, the energy produced by pumping cannot dissipate at scales ~ L. Then in the statistically steady state, the energy is transferred to small scales and dissipates here together with the enstrophy. Therefore, the large-scale motion has to be self-organized to ensure a smallness of the energy production rate Ė in comparison with ḢL2, where Ḣ is the enstrophy production rate. Simulations in the framework of two-dimensional compressible hydrodynamics with zero boundary conditions and without bottom friction and viscosity confirm both the existence of a direct enstrophy cascade and anomalously small energy production. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Boundary conditions

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Mathematical Modeling of Dynamic and Optical Effects in Ionospheric Experiments Using an Explosive Chemical Generator 22nd

Mathematical Modeling of Dynamic and Optical Effects in Iono...

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22nd International Conference on Computational Mechanics and Modern Applied Software Systems, CMMASS 2021

作者： Stupitsky, Evgeniy L. Motorin, Andrey A. Moiseeva, Darya S. Institute for Computer Aided Design of the Russian Academy of Sciences 19/18 Vtoraya Brestskaya ul. Moscow123056 Russia

ISBN: (纸本)9789811689253

A physical and numerical analysis of the dynamics and radiation of products of an explosion is given. We consider the explosions generated during the Russian-American experiment in the ionosphere using an explosive generator based on hexogen (RDX) and trinitrotoluene (TNT). The emission coefficients from the resulting perturbed region in the infrared spectral range are determined. A numerical analysis of the behavior of the products for the experiment at an altitude of 280 km is given. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Explosives

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Numerical Simulation of Combustion Wave Propagation in a Black Powder Charge Using a Two-Fluid Model 22nd

Numerical Simulation of Combustion Wave Propagation in a Bla...

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22nd International Conference on Computational Mechanics and Modern Applied Software Systems, CMMASS 2021

作者： Chuprov, Petr A. Institute of Computer Aided Design of the Russian Academy of Sciences 19/18 Vtoraya Brestskaya ul. Moscow123056 Russia

ISBN: (纸本)9789811689253

The chapter studies the process of propagation of a combustion wave along the charge of a heterogeneous explosive. Black gunpowder is considered as an explosive. The mathematical model is based on the Baer-Nunziato two-fluid system of equations and takes into account such physical processes as interphase exchange of mass, momentum, and energy. The numerical flux in the finite-volume computational algorithm is calculated using the Harten-Lax-van Leer scheme. Simulation results are compared with the reference calculated data obtained by other authors. The pressure curves on sensors located at several points along the channel are in good agreement. The calculation confirms the decisive role of the compaction process on the nature of the combustion wave propagation. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Explosives

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Numerical modeling of unsteady subsonic flow over the conical shape body 22

Numerical modeling of unsteady subsonic flow over the conica...

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22nd International Conference on Computational Mechanics and Modern Applied Software Systems, CMMASS 2021

作者： Babakov, A.V. Institute for Computer Aided Design The Russian Academy of Sciences 19/18 2-ya Brestskaya st. Moscow123056 Russia

The article presents the results of a numerical study of the unsteady vortex motion of gas arising over the conical body with a segmental bottom surface for various angles of attack in a subsonic flow regime. The simulation is based on the viscous compressible gas model (Navier-Stokes model). For various attack angles, the patterns of vortex flow around the conical surface of the body, in the area of its conjugation with the segmental bottom surface and in the near wake are presented. Data on non-stationary behavior and the magnitude of pressure in the conjugation area are given. For numerical simulation the method of finite volumes is used. Taking into account phenomena of the flow separation, the computational grids used have condensation to the surface of the body. Numerical calculations were carried out on the basis of parallel algorithms of the method and were realized on multiprocessor computing complexes. © Published under licence by IOP Publishing Ltd.

关键词： Flow separation

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Inductive Limit Switch Based on Chaotic Circuit with Double-Scroll Attractor 12

Inductive Limit Switch Based on Chaotic Circuit with Double-...

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12th Mediterranean Conference on Embedded Computing, MECO 2023

作者： Druzhina, Olga Isakov, Oleg Karimov, Artur Kolev, Georgii Karimov, Timur St. Petersburg Electrotechnical University Department of Computer-Aided Design St. Petersburg Russia Youth Research Institute St. Petersburg Electrotechnical University St. Petersburg Russia

ISBN: (纸本)9798350322910

Sensors based on chaotic oscillators comprise a promising direction in the field of nonlinear dynamics. Hypothetically, such sensors have improved sensitivity, selectivity, and rate. In this paper, we research and develop an inductive sensor based on the Sprott Case B chaotic oscillator, which features a double-scroll attractor. We propose a circuit implementation with inductive coil, and compare the results of the computer simulation with experimental study. We conclude that the proposed circuit is suitable for use as a limit switch to determine the position of a steel plate, as its dynamics is switching from chaotic to periodic regime at a certain adjustable distance between a coil and the plate. The performance obtained in the study is comparable with sensors of conventional design, but has the potential for improvement. © 2023 IEEE.

关键词： Inductive sensors

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Multi-regime fatigue failure model based on damage theory

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Procedia Structural Integrity 2023年 43卷 53-58页

作者： A.D. Nikitin I.S. Nikitin B.A. Stratula Institute of Computer Aided Design of RAS 2-nd Brestskaya str. 19/18 Moscow 123056 Russia

The prediction of a spatial fatigue crack development under arbitrary loading conditions is a complex problem. This paper introduces a new approach to predict crack initiation and propagation development based on damage theory. The fatigue degradation of the material within a physically small volume is described by the kinetic equation for damage function. The mechanical properties of the material (elastic moduli) depend on the damage function value. The uniform descriptions of the left and right branches of the full SN-curve allow the introduction of the general numerical procedure for fatigue ranges from HCF to VHCF. At the initial stage, the values of the damage function are calculated based on the elastic or elastic-plastic solution. The damage function is associated with two different mechanisms of fatigue damage accumulations. The first one is due to normal stress and the second one is due to shear. The contribution of each mechanism to damage function development is calculated simultaneously. As soon as the damage function gets the critical value the dominant mechanism is established. Therefore, the proposed multi regime model and numerical procedure are capable to predict crack initiation, spatial crack propagation and dominant crack opening mechanism at different stages of crack growth.

关键词： fatigue damage function mathematical modeling numerical simulation life prediction

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Chaos Shift Keying Coherent Communication Based on Different Types of Operational Amplifiers 12

Chaos Shift Keying Coherent Communication Based on Different...

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12th Mediterranean Conference on Embedded Computing, MECO 2023

作者： Kvitko, Dmitriy Babkin, Ivan Shirnin, Kirill Karimov, Timur Kolev, Georgii Rybin, Vyacheslav St. Petersburg Electrotechnical University Department of Computer-Aided Design St. Petersburg Russia Youth Research Institute St. Petersburg Electrotechnical University St. Petersburg Russia

ISBN: (纸本)9798350322910

This study focuses on exploring the potential of using different types of operational amplifiers (op-amps) in Chaos Shift Keying (CSK) coherent communication systems to improve performance and energy efficiency. CSK is a promising technology for secure and efficient communication that works on the principle of transmitting signals based on chaotic systems. This article presents an electronic circuit based on the Rössler system to demonstrate the transmission of data using CSK coherent chaotic communication systems. The results of this study may have practical implications for the design and implementation of CSK communication systems in various applications. © 2023 IEEE.

关键词： Operational amplifiers

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Enhanced Control System for the Oil Extraction Screw Press

Enhanced Control System for the Oil Extraction Screw Press

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International Conference on Perspective Technologies and Methods in MEMS design (MEMSTECH)

作者： Vitaliy Korendiy Oleksandr Kachur Volodymyr Havran Department of Technical Mechanics and Engineering Graphics Lviv Polytechnic National University Lviv Ukraine Department of Computer-Aided Design Lviv Polytechnic National University Lviv Ukraine

ISBN: (数字)9798350378627

ISBN: (纸本)9798350378634

Oil extraction screw presses are widely used in agriculture and food industry. In most cases, they are not equipped with complicated control systems due to the necessity of reducing their price and providing sufficient reliability. Therefore, such presses cannot reach the best efficiency (productivity, performance), while processing different seeds and kernels. The present paper is focused on development of the enhanced control allowing for monitoring the operational parameters of the screw press and adjusting them in accordance with user-defined technologically prescribed ones. The research methodology contains a thorough analysis of the press design and operational peculiarities, and the development of functional (block), circuit, and breadboard diagrams of the control system. In order to verify the initially stated ideas of control strategies, the simulation models of the control systems are implemented in the TinkerCAD and SolidWorks software, and the experimental prototype of the screw press is correspondingly improved. The presented control system and press regulation strategies can be effectively implemented by engineers and technologists while developing new and enhancing existing designs of screw presses.

关键词： Presses Solid modeling Oils Fasteners Control systems Software Regulation

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EXPLICIT SIMULATION OF SEISMIC WAVES IN FRACTURED VTI MEDIA 82

EXPLICIT SIMULATION OF SEISMIC WAVES IN FRACTURED VTI MEDIA

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82nd EAGE Conference and Exhibition 2021

作者： Golubev, V. Shevchenko, A. Moscow Institute of Physics and Technology Russia Institute of Computer Aided Design The RAS Russia

ISBN: (纸本)9781713841449

Precise numerical modelling of the wave propagation in geological media is crucially important for seismic inversion and migration techniques. Due to the sedimentation procedure the upper part of geological sections is anisotropic. For this reason, the velocity of the wave propagation depends on the propagation direction. One of the major cases is the vertical transverse isotropic (VTI) media. Different approaches were proposed for precise simulation of wavefields in such media. In this work we propose a novel approach for simulation of the dynamic behavior of the VTI fractured medium. It relies on the grid-characteristic numerical method on rectangular grids. It continues our activity of extending this method for different types of rheology. The method was successfully implemented as a part of our in-house software RECT and applied to the improved Marmousi2 model. Copyright© (2021) by the European Association of Geoscientists & Engineers (EAGE) All rights reserved.

关键词： Wave propagation

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Intelligent System for Predicting the Integrity of Operating Pipelines

Intelligent System for Predicting the Integrity of Operating...

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International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency (SUMMA)

作者： Kristina Evseenkova Galina Kuznetsova Department of Computer-Aided Design and Control Systems Saint-Petersburg State Institute of Technology Saint Petersburg Russian Federation

ISBN: (数字)9798331532178

ISBN: (纸本)9798331532185

An intelligent system for monitoring the integrity of operating pipelines is presented. The software package is designed to assess the corrosion rate and calculate the residual life of pipelines, which takes into account the parameters of climatic and transported environments, the characteristics of pipelines and their insulating coatings. The complex allows us to consider different types of corrosion: atmospheric, electrochemical and mechanical. A functional structure is proposed that describes the operating principle of the software package, calculation results and examples of intelligent system interfaces are presented.

关键词： Software packages Atmospheric modeling Corrosion Pipelines Predictive models Control systems Mathematical models Energy efficiency Intelligent systems Monitoring

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