numerical method

Розглянуто фрактальну модель тепло- та масоперенесення у капілярно-пористих матеріалах, що описується системою диференціальних рівнянь у частинних похідних з дробовим порядком. Різницевим методом отримано числовий розв’язок задачі для різних значень дробової похідної.

There was considered fractal model of heat and mass transfer in capillary-porous materials which is described by the system of differential equations in partial derivatives with fractional order. The difference method receives the numerical decision of a problem at various orders of a fractional derivative.

Розглянуто фрактальну модель неізотермічного вологоперенесення у капілярно- пористих матеріалах, що описується системою диференціальних рівнянь у частинних похідних з дробовим порядком. Різницевим методом отримано числовий розв’язок задачі для різних значень дробової похідної.

The article presents a three-dimensional mathematical model of the gas filtration process in porous media and a numerical algorithm for solving the initial-boundary value problem.  The developed model is described using the nonlinear differential equation in partial derivatives with the appropriate initial and boundary conditions.  The proposed mathematical apparatus makes it possible to carry out hydrodynamic calculations taking into account changes in the main factors affecting the process under consideration: permeability, porosity, and thickness of layers, gas recovery coefficient, visc

The reliability and safe operation of mechanical elements of rail transport is an important and relevant scientific and technical issue since high-loaded units and elements of its chassis are exposed to prolonged operation and their failure can lead to damage with catastrophic consequences. To prevent the possible failure of such objects, there is a necessity for a reliable estimation of their residual life.

The resilient muff of a near-zero inflexibility is considered. The dependence and method of mounting of muff’s resilient moment are given. The simple but effective numerical method for the construction of skeletal curves is suggested. It is shown that a skeletal curve for a muff with the area of negative inflexibility has two branches.

The models of gas movement in pipelines and gas filtration processes in complex porous media are considered in entire and fractional derivatives. The method for linearization of equations, which are included in the mathematical model of mass transfer, is suggested as well as an iterative scheme for solving initial systems of nonlinear differential equations is constructed. The finite-element model of the problem with the use of the Petrov-Galerkin method and Grunwald-Letnikov scheme concerning derivatives of the fractional order are implemented.