Papers by Artem Yakunchikov
Computational mathematics and mathematical physics, Dec 1, 2023
Fluid Dynamics, Sep 1, 2012
The results of the molecular-dynamic modeling of hydrogen molecule scattering on a graphite surfa... more The results of the molecular-dynamic modeling of hydrogen molecule scattering on a graphite surface are compared with the scattering models of Maxwell, Epstein, and Cercignani-Lampis. The advantages and shortcomings of the above-listed models are analyzed under different conditions. A new scattering kernel is proposed; it represents a combination of the Epstein and Cercignani-Lampis models and is in better agreement with the results of trajectory calculations.
Fluid Dynamics, Jun 1, 2009
ABSTRACT The hydrogen adsorption in carbon nanotubes arrays was studied through molecular dynamic... more ABSTRACT The hydrogen adsorption in carbon nanotubes arrays was studied through molecular dynamics simulation. The interactions are described by the Lennard–Jones potential. The relative mass content and density of hydrogen are obtained as functions of the pressure, temperature and the distance between the tubes in the array. The formation of a second adsorption layer at low temperatures is detected. The cluster geometry optimal for adsorption is found.
Moscow University Mechanics Bulletin, Apr 1, 2007
A dynamic model for the Monte Carlo method is developed to analyze the atom recombination on a ca... more A dynamic model for the Monte Carlo method is developed to analyze the atom recombination on a catalytic surface. A numerical method for the study of this model is considered. The concentrations of physically and chemically adsorbed atoms obtained using this approach are in good agreement with experimental data and with the numerical results obtained on the basis of the phenomenological model and by other authors with the aid of the Monte Carlo method.
27TH INTERNATIONAL SYMPOSIUM ON RAREFIED GAS DYNAMICS, 2011
The scattering of hydrogen molecules from graphite surface was studied through molecular dynamics... more The scattering of hydrogen molecules from graphite surface was studied through molecular dynamics simulation. The trajectories of the hydrogen molecules and surface atoms were calculated. The distributions of velocity and energy after reflection were obtained depending on direction and quantity of the initial velocity. The energy and tangential momentum accommodation coefficients were calculated for cases where incident velocity distribution can be approximated by maxwellian function and mean velocity is negligible. Obtained coefficients are in satisfactory agreement with experimental data.
Journal of physics, Feb 3, 2016
Moscow University Mechanics Bulletin, Sep 1, 2015
Physics of Fluids, Feb 1, 2021
This article continues our cycle devoted to comprehensive investigation of the diatomic molecule ... more This article continues our cycle devoted to comprehensive investigation of the diatomic molecule collision process. In this paper, we focus particularly on the in-depth study of the rotational–translational (R–T) energy exchange process and Borgnakke–Larsen (BL) energy exchange model used in the direct simulation Monte Carlo method. The present study, which was performed on several levels of description (molecular, microscopic, and macroscopic), is based mainly on the highly detailed dataset (around 1011 configurations) of binary N2–N2 collisions, obtained via the classical trajectory calculation (CTC) method. This dataset, along with the explicit mathematical representation of the Borgnakke–Larsen model derived in the present paper, allowed us to obtain new results regarding the R–T energy exchange process: (1) we present an ab initio method to derive physically accurate expressions for inelastic collision probability pr in the BL model directly from CTC data; (2) we present a new two-parametric model for pr and compared it to the previously known models, including the recent nonequilibrium-direction-dependent model of Zhang et al. [“Nonequilibrium-direction-dependent rotational energy model for use in continuum and stochastic molecular simulation,” AIAA J. 52(3), 604 (2014)]; (3) it showed that apart from the well-known dependence of the rotational relaxation rate on “direction to equilibrium” (ratio between translational and rotational temperatures), on molecular scale, rotationally over-excited molecule pairs demonstrate almost zero energy transfer to the translational energy mode (even in the case of very significant discrepancies between translational and rotational energies); (4) it was also shown that the Borgnakke–Larsen approach itself may require reassessment since it fails to give a proper description of distribution of post-collision energies. Throughout this paper, we also tried to put together and analyze the existing works studying the rotational relaxation process and estimating the rotational collision number Zrot by performing reviews and assessment of (1) numerical approaches to simulate non-equilibrium problems, (2) models for inelastic collision probabilities pr, (3) approaches to estimate Zrot, and (4) intermolecular potentials used for molecular dynamics and CTC simulations. The corresponding conclusions are given in this paper.
Microfluidics and Nanofluidics, Oct 15, 2014
Free-molecular gas flow through a membrane oscillating in its own plane is investigated. The prob... more Free-molecular gas flow through a membrane oscillating in its own plane is investigated. The probability of the passage through the membrane by gas molecules is calculated as a function of dimensionless parameters characterizing the channel geometry, the molecular mass, the gas temperature, and the membrane oscillation frequency and amplitude. It is shown that the membrane permeability for one or another gas can be controlled by means of changing the forced oscillation parameters.
Physics of Fluids, 2021
This article continues our cycle devoted to comprehensive investigation of the diatomic molecule ... more This article continues our cycle devoted to comprehensive investigation of the diatomic molecule collision process. In this paper, we focus particularly on the in-depth study of the rotational–translational (R–T) energy exchange process and Borgnakke–Larsen (BL) energy exchange model used in the direct simulation Monte Carlo method. The present study, which was performed on several levels of description (molecular, microscopic, and macroscopic), is based mainly on the highly detailed dataset (around 1011 configurations) of binary N2–N2 collisions, obtained via the classical trajectory calculation (CTC) method. This dataset, along with the explicit mathematical representation of the Borgnakke–Larsen model derived in the present paper, allowed us to obtain new results regarding the R–T energy exchange process: (1) we present an ab initio method to derive physically accurate expressions for inelastic collision probability pr in the BL model directly from CTC data; (2) we present a new ...
IOP Conference Series: Materials Science and Engineering, 2018
Microfluidics and Nanofluidics, 2018
Numerical simulation of a free-molecular gas flow through plane microchannel with walls performin... more Numerical simulation of a free-molecular gas flow through plane microchannel with walls performing forced curving motion according to sine law is presented. It is shown that the probability of gas molecules to pass through the channel significantly depends on relation between wave speed of walls harmonic oscillations and characteristic thermal speed of gas molecules. It is then shown how this effect can be utilized for gas separation, and the comprehensive study of the influence of the main parameters (channel width and length, wave amplitude and length, etc.) on the magnitude of effect is performed.
Moscow University Mechanics Bulletin, 2015
Microfluidics and Nanofluidics, 2014
Free-molecular gas flow through a membrane oscillating in its own plane is investigated. The prob... more Free-molecular gas flow through a membrane oscillating in its own plane is investigated. The probability of the passage through the membrane by gas molecules is calculated as a function of dimensionless parameters characterizing the channel geometry, the molecular mass, the gas temperature, and the membrane oscillation frequency and amplitude. It is shown that the membrane permeability for one or another gas can be controlled by means of changing the forced oscillation parameters.
Moscow University Mechanics Bulletin, 2007
A dynamic model for the Monte Carlo method is developed to analyze the atom recombination on a ca... more A dynamic model for the Monte Carlo method is developed to analyze the atom recombination on a catalytic surface. A numerical method for the study of this model is considered. The concentrations of physically and chemically adsorbed atoms obtained using this approach are in good agreement with experimental data and with the numerical results obtained on the basis of the phenomenological model and by other authors with the aid of the Monte Carlo method.
Fluid Dynamics, 2012
The results of the molecular-dynamic modeling of hydrogen molecule scattering on a graphite surfa... more The results of the molecular-dynamic modeling of hydrogen molecule scattering on a graphite surface are compared with the scattering models of Maxwell, Epstein, and Cercignani-Lampis. The advantages and shortcomings of the above-listed models are analyzed under different conditions. A new scattering kernel is proposed; it represents a combination of the Epstein and Cercignani-Lampis models and is in better agreement with the results of trajectory calculations.
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Papers by Artem Yakunchikov