scholarly journals Математическое моделирование распространения верховых лесных пожаров при наличии противопожарных разрывов и заслонов

2019 ◽  
Vol 89 (8) ◽  
pp. 1141
Author(s):  
В.И. Марзаева
Keyword(s):  
Forest Fires ◽  
Control Volume ◽  
Discrete Analogue ◽  
Control Volume Method ◽  
Crown Fire ◽  
Hardwood Trees ◽  
Volatile Products ◽  
Volume Method ◽  
Forest Combustible ◽  
Fire Stops

Using the method of mathematical modeling, the process of spreading forest fires in the presence of fire breaks and barriers consisting of hardwood trees was studied. Mathematically, this problem is reduced to solving the Reynolds equations for turbulent flow, taking into account chemical reactions. To obtain a discrete analogue, the control volume method was used. Using numerical calculations, we obtained the distributions of the fields of velocity, temperature, oxygen concentrations, volatile products of pyrolysis, combustion and volume fractions of the condensed phase. The model allowed us to obtain contours of the spread of forest fires, which depend on the stock and type of forest combustible materials, moisture content, velocity and direction of wind, etc. It was also possible to determine the dependence of the sizes of fire breaks and barriers on the above parameters, at which the crown fire stops spreading.

scholarly journals Mathematical modeling of the initiation and spread of forest fires and their impact on buildings and structures

2020 ◽  
Vol 99 (3) ◽  
pp. 54-61
Author(s):  
V.A. Perminov ◽  
◽  
K.O. Fryanova ◽  
Keyword(s):  
Mathematical Modeling ◽  
Forest Fire ◽  
Forest Fires ◽  
Control Volume ◽  
Fire Spread ◽  
Discrete Analogue ◽  
Temperature Fields ◽  
Emergency Situations ◽  
Volume Method ◽  
Fire Spreading

Currently, methods of mathematical modeling are used to study processes in emergency situations. Forest fires are extremely complex and destructive natural phenomena which depend on availability of fuel, meteorological and other conditions. Mathematical model of forest fire is based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the theoretical study of the problems of crown forest fire spread in windy condition and their thermal impact on the wooden building were carried out. The research was based on numerical solution of two-dimensional Reynolds equations. The boundary-value problem is solved numerically using the method of splitting according to physical processes. A discrete analogue for the system of equations was obtained by means of the control volume method. A study of forest fire spreading made it possible to obtain a detailed picture of the change of the component concentration of gases and temperature fields in forest fire and on the wall of building with time. It let to determine the limiting distances between forest fire and building for possibility of wooden walls ignition for different meteorology conditions, size of building and intensity of fire impact.

scholarly journals A New Formulation of Maxwell’s Equations

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 868
Author(s):  
Simona Fialová ◽  
František Pochylý
Keyword(s):  
Numerical Methods ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Control Volume ◽  
Control Volume Method ◽  
Integral Forms ◽  
New Formulation ◽  
Electrical Induction ◽  
Volume Method ◽  
Integral Identities

In this paper, new forms of Maxwell’s equations in vector and scalar variants are presented. The new forms are based on the use of Gauss’s theorem for magnetic induction and electrical induction. The equations are formulated in both differential and integral forms. In particular, the new forms of the equations relate to the non-stationary expressions and their integral identities. The indicated methodology enables a thorough analysis of non-stationary boundary conditions on the behavior of electromagnetic fields in multiple continuous regions. It can be used both for qualitative analysis and in numerical methods (control volume method) and optimization. The last Section introduces an application to equations of magnetic fluid in both differential and integral forms.

scholarly journals A Framework and Numerical Solution of the Drying Process in Porous Media by Using a Continuous Model

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Hong Thai Vu ◽  
Evangelos Tsotsas
Keyword(s):  
Porous Media ◽  
Control Volume ◽  
Continuous Model ◽  
Control Volume Method ◽  
Drying Process ◽  
Transport Parameters ◽  
Governing Equations ◽  
Numerical Tools ◽  
Volume Method ◽  
The Continuum

The modelling and numerical simulation of the drying process in porous media are discussed in this work with the objective of presenting the drying problem as the system of governing equations, which is ready to be solved by many of the now widely available control-volume-based numerical tools. By reviewing the connection between the transport equations at the pore level and their up-scaled ones at the continuum level and then by transforming these equations into a format that can be solved by the control volume method, we would like to present an easy-to-use framework for studying the drying process in porous media. In order to take into account the microstructure of porous media in the format of pore-size distribution, the concept of bundle of capillaries is used to derive the needed transport parameters. Some numerical examples are presented to demonstrate the use of the presented formulas.

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