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Generation of transparent boundary conditions for modeling wave propagation in anisotropic media
No full textAbstract:
The preprint contains results on development of mathematical foundations and numerical approaches of generating transparent boundary conditions (TBCs) for orthotropic anisotropic elastic media. A two-dimensional wave propagation problem in polar coordinates (r, θ) is considered.Note:
Research direction:Mathematical problems and theory of numerical method
To the development of statistical thermodynamics and technique оf fractal analysis for non-extensive systems based on entropy and discrimination information of Renyi
No full textAbstract:
The article shows how one can obtain statistical thermodynamics of nonextensive systems and determine its properties on the basis of parametric entropy and discrimination information of Renyi. This exploration is based on not Gibbsian equilibrium distribution obtained from the extremum condition Renyi entropy, while preservation an average energy of the system, as well as on the averaging of its of random parameters over an escort (normalized) distribution, convenient when considering the chaotic, fractal and multifractal systems. It is shown that in the microcanonical ensemble the Renyi statistic is equivalent to Boltzmann−Gibbs statistics. It is found that the temporal evolution of a closed stochastic system to the equilibrium state depends on the sign of the parameter , which is a measure of the nonextensivity of Renyi statistics. Discusses different ways of constructing measures different orders of multifractales on the basis of entropy and discrimination information of Renyi and analyzed their specifics.Note:
Research direction:Mathematical modelling in actual problems of science and technic
Systems of quasi-linear equations with the same principal part and hydrodynamic substitution
No full textAbstract:
The possibility of using the Monge potentials for the purpose of construction for dynamical systems of Liouville-Jacobi equations and application of a modified hydrodynamic substitution to them.Note:
Research direction:Mathematical problems and theory of numerical method
Terminal Control Algorithm for Descent from Near-Earth Orbit with Landing in Given Region
No full textAbstract:
The reentry vehicle control for descent from near-Earth orbit under significant disturbances is considered. The method of automatically shift of de-orbit point as well as adaptation to real motion conditions and modification of reference roll function to satisfy given restrictions on landing accuracy, load factor and propellant consumption are suggested. The landing within restricted region of Russian Federation is provided.Note:
Research direction:Theoretical and applied problems of mechanic
Refinement of the geomagnetic perturbation index by processing orbit measurements of a test satellite
No full textAbstract:
We describe the refinement of the geomagnetic perturbation index Kpby processing radio tracking data of the orbital motion of a simplest test satellite. A test satellite has the shape of a sphere and a constant ballistic coefficient. Approximation of its orbital data by solutions of quite accurate motion equations allows specifying the index Kpin the atmospheric density model used to calculate the satellite aerodynamic drag. We demonstrate this approach by processing the data of the satellite Sphere launched from the ISS in August 2012. Orbit measurements were performed by the Russian means of passive radar system several times a day. For checking we also used orbital data generated by the two-line elements of the orbit of this satellite. Clarification of the approach is also confirmed by the results of statistical modeling.Note:
Research direction:Theoretical and applied problems of mechanic
Quantum computation model: the classical programmer's viewpoint
No full textAbstract:
Building the working prototypes of many-qubit quantum computers advance rapidly during the last few years. Number of possible implementations of quantum computers, together with the number of sample quantum algorithm implementations, grow rapidly as well. It seems necessary to involve much more HPC experts in those works than it is done today. A big problem in doing this is an absolutely unacceptable way in which quantum computation model is traditionally explained today to classical programmers. In our work we tried to contribute to the solution of this problem.Note:
Research direction:Programming, parallel computing, multimedi
Mathematical model of multicomponent mixture flow of gases with regard to the possibility of the liquid phase
No full textAbstract:
A mathematical model of the multicomponent gaseous flow supplied by main closing relations is presented. The level of detalization is related to the planned creation of a computational methodology and a computer code for calculating multicomponent and two-phase flows. This presentation is excluded multiphase and turbulence models which will be considered in future work.Note:
Research direction:Mathematical modelling in actual problems of science and technic
Export of metadata of Keldysh Institute Preprints
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The meta-information about preprints is entered the database of the electronic library of Keldysh Institute publications and then exported to external storages, such as eLibrary and CrossRef. To ensure the effective operation of search engines a site map of preprints is built. Additional efforts are made for the correct indexing of preprints by the Google Scholar search engine.Note:
Research direction:Programming, parallel computing, multimedi
Numerical algorithm for two-dimensional three-phase mathematical model of forest fires
No full textAbstract:
For the developed earlier by the authors two-dimensional three-phase mathematical model of forest fires, a numerical solution algorithm based on the method of splitting the model system of equations into several subsystems by physical processes was created. The subsystems of the equations are approximated by the finite-difference method. The results of numerical simulation showing that the developed model adequately represents the forest fires propagation process.Note:
Research direction:Mathematical modelling in actual problems of science and technic
Gravity assists near Venus for reaching positions over ecliptic. Resonant asymptotic velocity
No full textAbstract:
Venus, the closest neighbor of the Earth in the Solar system, is primarily suitable for the spacecraft gravity assists maneuvers in order to low-cost orbit inclination changing relative to the Ecliptic. The 'resonance' values of the spacecraft asymptotic velocity relative to the planet are calculated. Their implementation allows the increasing of the inclination of the spacecraft orbit by means of gravity assists without jumping between neighboring synchronisms along the invariant lines of the main resonances on the V∞-sphere up until to the pole of the maximum inclination. The Venusian cometary invariant is calculated, which not changes with the gravity assists near Venus. An adaptive semi-analytical and geometrically distinct technique for the synthesis of chains of gravity assists near Venus for low-cost changes of the spacecraft’s orbit inclination is presented.Note:
Research direction:Theoretical and applied problems of mechanic