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Wyszukujesz frazę "Euler method" wg kryterium: Temat


Tytuł:
Analysis of the influence of the finite elements mesh density on the determined shaped charge jet parameters
Autorzy:
Panowicz, R.
Konarzewski, M.
Borkowski, J.
Milewski, E.
Tematy:
charge jet
finite element method
Euler method
Pokaż więcej
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Powiązania:
https://bibliotekanauki.pl/articles/244994.pdf  Link otwiera się w nowym oknie
Opis:
Article presents results of numerical analyses of the finite elements mesh density influence on the shaped charge jet stream formation process and its selected parameters. Authors considered classical shaped charge, which consists of the plastic explosive material, copper liner and aluminium case. To properly described, material properties of the liner and case of the shaped charge, the Johnson-Cook material model was used. Detonation process was described using burn model approach. Behaviour of the detonation process products was described by commonly used John-Wilkins-Lee equation of state. Due to the nature of the presented phenomenon, in which we are dealing with large strains and strain rates, for its modelling authors utilized Euler description, implemented in the LS-Dyna software. In these method material flows by the finite elements and mesh is not deformed. Such approach allows for modelling phenomena where large and very large deformations occur. Unfortunately, it can result in a destabilizing of the systems energy balance. In order to minimize dissipation processes, in calculations was used second order scheme because of the spatial variables and time. Analyses were performed in axially symmetric setup, which was possible due to the symmetry of the analysed system. Influence of the finite elements size on the process of jet stream formation and its selected parameters was analysed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topological conjugacy of cascades generated by gradient flows on the two-dimensional sphere
Autorzy:
Bielecki, Andrzej
Tematy:
topological conjugacy
gradient dynamical system
Euler method
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Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Powiązania:
https://bibliotekanauki.pl/articles/1208030.pdf  Link otwiera się w nowym oknie
Opis:
This article presents a theorem about the topological conjugacy of a gradient dynamical system with a constant time step and the cascade generated by its Euler method. It is shown that on the two-dimensional sphere S² the gradient dynamical flow is, under some natural assumptions, correctly reproduced by the Euler method for a sufficiently small time step. This means that the time-map of the induced dynamical system is globally topologically conjugate to the discrete dynamical system obtained via the Euler method.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected aspects of modelling a phenomena occurring with very large strain rates on the example of the shaped charge jet stream forming process and explosive formed projectiles
Autorzy:
Panowicz, R.
Konarzewski, M.
Borkowski, J.
Milewski, E.
Tematy:
charge jet
EFP
finite element method
Euler method
Pokaż więcej
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Powiązania:
https://bibliotekanauki.pl/articles/245630.pdf  Link otwiera się w nowym oknie
Opis:
During the process of the shaped charge jet stream formation and creation of the explosive formed projectiles, we have to deal with strain rates reaching level of 107 1/s and strains larger than in other dynamic phenomena. Therefore, the correct numerical analyses of such problems are especially demanding, both in terms of preparation of the numerical model and time needed for obtaining the solution. For their execution, both meshfree and Euler description based computational methods are used. Due to very large deformations and associated with them numerical analyses errors, computational methods based on the Lagrange description are not used. Description of the materials behaviour has to take into account influence of the strain rate in wide range of parameters. In most cases, it is realized by using in computational analyses Johnson-Cook or Steiberg-Green constitutive models. These models provide an accurate description of the material parameters not only in the wide range of strain rates, but also in large scope of strains and temperatures. Article presents results of the numerical analyses concerning the influence of selected numerical and geometric parameters of the system on the process of shaped charge jet stream formation and creation of explosive formed projectile.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulations for Solving Fuzzy Fractional Differential Equations by max-min Improved Euler Methods
Autorzy:
Khan, N. A.
Razzaq, O. A.
Riaz, F.
Tematy:
fuzzy
improved Euler method
numerical solution
Mathematica 10
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Wydawca:
Społeczna Akademia Nauk w Łodzi
Powiązania:
https://bibliotekanauki.pl/articles/108688.pdf  Link otwiera się w nowym oknie
Opis:
In this paper, an extension is introduced into Max-Min Improved Euler methods for solving initial value problems of fuzzy fractional differential equations (FFDEs). Two modified fractional Euler type methods have been proposed and investigated to obtain numerical solutions of linear and nonlinear FFDEs. The proposed algorithms are tested on various illustrative examples. Exact values are also simulated to compare and discuss the closeness and accuracy of approximations so obtained. Comparatively, tables and graphs results reveal the complete reliability, efficiency and accuracy of the proposed methods.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cauchy Multiplication of Euler Summable Series in Ultrametric Fields
Autorzy:
Deepa, R.
Natarajan, P N
Srinivasan, V.
Tematy:
ultrametric field, regular method, euler summability method,Cauchy product
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Wydawca:
Polskie Towarzystwo Matematyczne
Powiązania:
https://bibliotekanauki.pl/articles/746653.pdf  Link otwiera się w nowym oknie
Opis:
Euler summability method in a complete, non-trivially valued, ultrametric field of the characteristic zero was introduced by Natarajan in [7]. Some properties of the Euler summability method in such fields were studied in [2] and [7]. The purpose of the present note is to continue the study and to prove a pair of theorems on the Cauchy product of Euler summable sequences and series.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple discrete SIS criss-cross model of tuberculosis in heterogeneous population of homeless and non-homeless people
Dyskretny krzy»owy model rozprzestrzeniania się gruźlicy w niejednorodnej populacji bezdomnych i niebezdomnych
Autorzy:
Bodzioch, Mariusz
Choiński, Marcin
Tematy:
tuberculosis
discretization
explicit euler method
discrete
dynamical system
local stability
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Wydawca:
Polskie Towarzystwo Matematyczne
Powiązania:
https://bibliotekanauki.pl/articles/953421.pdf  Link otwiera się w nowym oknie
Opis:
Zaproponowany został dyskretny krzyżowy model rozprzestrzeniania się gruźlicy w niejednorodnej populacji składającej się z bezdomnych i niebezdomnych. Model ten oparty jest na prostym modelu typu SIS z dwuliniową funkcją transmisji i stałym napływem w obu populacjach. Przeprowadzona została wstępna analiza stabilności stanów stacjonarnych. Pokazano, że aby kontrolować rozprzestrzenianie się choroby zakaźnej w niejednorodnej populacji nie jest wystarczające rozważanie dynamiki choroby w kżdej podpopulacji oddzielnie. Parametry modelu zostały dopasowane do danych z województwa warmińsko-mazurskiego.
In this paper we propose a discrete criss-cross model of tuberculosis (TB) transmission in a heterogeneous population, which consists of two different subpopulations: homeless and non-homeless people. This criss-cross model is based on the simple continuous SIS model with bilinear transmission function and constant inflow into both subpopulations considered previously by us. We make preliminary stability analysis. We show that to control the spread of the infectious disease in a heterogeneous population it is not enough to consider the dynamics of the disease in each subpopulation separately. This result is consistent with the result for continuous model. We also fit the model to epidemic data from Warmian-Masurian Province of Poland.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A CFD model of a two-phase mixture flow in a test stand for air-borne particle analysis
Autorzy:
Stachnik, M.
Czachor, G.
Jakubowski, M.
Tematy:
CFD model
Euler method
two-phase flow
aerosol
air-borne particles
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Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Powiązania:
https://bibliotekanauki.pl/articles/297802.pdf  Link otwiera się w nowym oknie
Opis:
Farmers come across many materials which when being handled generate dust clouds. Even with low concentration these might pose risk of explosion and can carry dangerous microorganisms. To broaden the knowledge about fine dust particles sedimentation and analyze process of particles becoming air-borne, a tunnel air cleaner was designed. Based on the experiment, a CFX simulation was performed using the Eulerian approach and the CFX12.1 software. Presented model is a stedy state two-phase analysis of dust sedimentation. The results show mechanism of dust dispertion over large distance, such as regions of vorticity that seem to be main motor. Presented analysis emphasizes how easily small particles can become resuspended in the air and carried over distance. Acquired knowledge can be applied for safety regulation in many branches of agriculture.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical model of architecture and learning processes of artificial neural networks
Autorzy:
Bielecki, A.
Tematy:
artificial neural networks
neuron
learning process
topological conjugacy
gradient dynamical system
Euler method
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Wydawca:
Politechnika Gdańska
Powiązania:
https://bibliotekanauki.pl/articles/1931575.pdf  Link otwiera się w nowym oknie
Opis:
A mathematical model of architecture and learning processes of multilayer artificial neural netwoks is discussed in the paper. Dynamical systems theory is used to describe the learning precess of networks consisting of linear, weakly nonlinear and nonlinear neurons. Conjugacy between a gradient dynamical system with a constant time step and a cascade generated by its Euler method theorem is applied as well.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of a Solidification Problem
Autorzy:
Aboulaich, R.
Haggouch, I.
Souissi, A.
Tematy:
optymalizacja
metoda elementów skończonych
Stefan problem
free boundary
shape optimization
Euler method
finite element method
Pokaż więcej
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:
https://bibliotekanauki.pl/articles/908072.pdf  Link otwiera się w nowym oknie
Opis:
A two-dimensional Stefan problem is usually introduced as a model of solidification, melting or sublimation phenomena. The two-phase Stefan problem has been studied as a direct problem, where the free boundary separating the two regions is eliminated using a variational inequality (Baiocci, 1977; Baiocchi et al., 1973; Rodrigues, 1980; Saguez, 1980; Srunk and Friedman, 1994), the enthalpy function (Ciavaldini, 1972; Lions, 1969; Nochetto et al.., 1991; Saguez, 1980), or a control problem (El Bagdouri, 1987; Peneau, 1995; Saguez, 1980). In the present work, we provide a new formulation leading to a shape optimization problem. For a semidiscretization in time, we consider an Euler scheme. Under some restrictions related to stability conditions, we prove an L^2-rate of convergence of order 1 for the temperature. In the last part, we study the existence of an optimal shape, compute the shape gradient, and suggest a numerical algorithm to approximate the free boundary. The numerical results obtained show that this method is more efficient compared with the others.
Dostawca treści:
Biblioteka Nauki
Artykuł

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