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Wyszukujesz frazę "Helmholtz's equation" wg kryterium: Temat

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    Wyświetlanie 1-11 z 11
    Tytuł:
    Acoustic Scattering of 3D Complex Systems Having Random Rough Surfaces by Scalar Integral Equations
    Autorzy:
    Guel-Tapia, J. A.
    Villa-Villa, F.
    Mendoza-Suárez, A.
    Pérez-Aguilar, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/178120.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    integral equations
    Helmholtz equation
    acoustic scattering
    Opis:
    We propose a numerical surface integral method to study complex acoustic systems, for interior and exterior problems. The method is based on a parametric representation in terms of the arc’s lengths in curvilinear orthogonal coordinates. With this method, any geometry that involves quadric or higher order surfaces, irregular objects or even randomly rough surfaces can be considered. In order to validate the method, the modes in cubic, spherical and cylindrical cavities are calculated and compared to analytical results, which produced very good agreement. In addition, as examples, we calculated the scattering in the far field and the near field by an acoustic sphere and a cylindrical structure with a rough cross-section.
    Źródło:
    Archives of Acoustics; 2016, 41, 3; 461-472
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Methods for Classification of Tactile Patterns in General Position by Helmholtzs Equation
    Autorzy:
    Volf, J.
    Dvorak, M.
    Vlcek, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/384955.pdf
    Data publikacji:
    2008
    Wydawca:
    Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
    Tematy:
    pattern recognition
    Helmholtz's equation
    tactile image
    tactile information
    Opis:
    This paper describes new and original methods of tactile pattern recognition in general position applying the solution of Helmholtz's equation for a tactile transducer. Three groups of methods have been formed, based on: (a) calculation of the A matrix eigen value, with the matrix being formed either from the whole pattern, or from the limit points; (b) the scalar characteristic distribution of the components of the pattern's A matrix; (c) the geometrical properties of the A matrix of the pattern. The patterns have been classified into five groups.
    Źródło:
    Journal of Automation Mobile Robotics and Intelligent Systems; 2008, 2, 4; 59-63
    1897-8649
    2080-2145
    Pojawia się w:
    Journal of Automation Mobile Robotics and Intelligent Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mesh-free approach to Helmholtz equation based on radial basis functions
    Autorzy:
    Kowalczyk, P.
    Mrozowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/309385.pdf
    Data publikacji:
    2005
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    Helmholtz equation
    radial basis functions
    meshfree method
    cylindrical waveguides
    Opis:
    Recently, a radial basis functions (RBFs) method, which was originally proposed for interpolation problems, has been developed and applied to solve partial differential equations and eigenproblems. Properties of that method (meshfree algorithm) allows one to use it in many areas, including electromagnetics. In this paper the mesh-free RBF method for solving Helmholtz equation was applied and a new adaptive algorithm for defining the set of interpolation centers was proposed. Using the proposed approach the cutoff wavelengths and the field distribution in cylindrical waveguides of arbitrary cross-section were calculated with a high accuracy.
    Źródło:
    Journal of Telecommunications and Information Technology; 2005, 2; 71-74
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmission problems for the Helmholtz equation for a rectilinear-circular lune
    Autorzy:
    Denysenko, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/255476.pdf
    Data publikacji:
    2007
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    Helmholtz equation
    transmission problem
    infinite system of linear algebraic equations
    Opis:
    The question related to the construction of the solution of plane transmission problem for the Helmholtz equation in a rectilinear-circular lune is considered. An approach is proposed based on the method of partial domains and the principle of reflection for the solutions of the Helmholtz equation through the segment.
    Źródło:
    Opuscula Mathematica; 2007, 27, 2; 197-203
    1232-9274
    2300-6919
    Pojawia się w:
    Opuscula Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dirichlet/Dirichlet and Dirichlet/Dirichlet-Neumann/Neumann non-overlapping iterative domain decomposition methods
    Autorzy:
    Kubacki, S.
    Bogusławski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933184.pdf
    Data publikacji:
    2008
    Wydawca:
    Politechnika Gdańska
    Tematy:
    non-overlapping domain decomposition method
    parallel computing
    spectral methods
    Helmholtz equation
    Opis:
    A new iterative non-overlapping domain decomposition method is proposed for solving the one- and two-dimensional Helmholtz equation on parallel computers. The spectral collocation method is applied to solve the Helmholtz equation in each subdomain based on the Chebyshev approximation, while the patching conditions are imposed at the interfaces between subdomains through a correction, being a linear function of the space coordinates. Convergence analysis is performed for two applications of the proposed method (DDLC and DDNNLC algorithms - the meaning of these abbreviations is explained below) based on the works of Zanolli and Funaro et al. Numerical tests have been performed and results obtained using the proposed method and other iterative algorithms have been compared. Parallel performance of the multi-domain algorithms has been analyzed by decomposing the two-dimensional domain into a number of subdomains in one spatial direction. For the one-dimensional problem, convergence of the iteration process was quickly obtained using the proposed method, setting a small value of the ? constant in the Helmholtz equation. Another application of the proposed method may be an alternative to other iterative schemes when solving the two-dimensional Helmholtz equation.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2008, 12, 1-2; 85-104
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of Novel method of spherical aberration correction for enhanced spherical hybrid reflector antennas
    Badanie nowej metody korekcji aberacji sferycznej dla wzmocnionych sferycznych anten hybrydowych
    Autorzy:
    Ponomarev, O. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/118542.pdf
    Data publikacji:
    2010
    Wydawca:
    Politechnika Koszalińska. Wydawnictwo Uczelniane
    Tematy:
    spherical aberration
    hybrid reflector antennas
    Helmholtz equation
    aberracja sferyczna
    anteny hybrydowe
    równanie Helmholtza
    Źródło:
    Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej; 2010, 2; 77-92
    1897-7421
    Pojawia się w:
    Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modeling of the two-dimensional flow caused by sea conditions and wind stresses on the example of Dead Vistula
    Autorzy:
    Zima, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/258456.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    two-dimensional model of flow
    bi-harmonic Helmholtz equation
    hydrodynamics of water flow
    Opis:
    The article presents the results of two-dimensional modeling of flows caused by the sea conditions and wind stresses on the example of Dead Vistula. Based on the available bathymetric data, a numerical model of the river section was created, which was supplemented with data on the position of the water table depending on hydrometeorological conditions. To describe the flow field in steady conditions, a simplified model of two-dimensional flow in the form of the bi-harmonic Helmholtz equation for the current function has been adopted, taking into account additional impacts caused by wind stresses on the water surface. Then the current function was converted into the velocity vector components. This equation, supplemented with appropriate boundary conditions, has been solved numerically using the finite difference method. On the basis of the available literature, 4 variants of hydrometeorological conditions were adopted, depending on the direction and strength of wind and sea conditions. The obtained results were compared with the results of published measurements taken on the studied section of the river. These calculations were the basis for the implementation of a two-dimensional model of the spread of pollutants in the studied section of the Dead Vistula.
    Źródło:
    Polish Maritime Research; 2018, S 1; 166-171
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The reactance wave diffraction problem by a strip in a scale of Bessel potential spaces
    Autorzy:
    Castro, L. P.
    Natroshvili, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/255627.pdf
    Data publikacji:
    2006
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    Helmholtz equation
    boundary-transmission problem
    wave diffraction
    convolution type operator
    Wiener-Hopf operator
    Fredholm property
    factorization
    Opis:
    We consider a boundary-transmission problem for the Helmholtz equation, in a Bessel potential space setting, which arises within the context of wave diffraction theory. The boundary under consideration consists of a strip, and certain reactance conditions are assumed on it. Operator theoretical methods are used to deal with the problem and, as a consequence, several convolution type operators are constructed and associated to the problem. At the end, the well-posedness of the problem is shown for a range of regularity orders of the Bessel potential spaces, and for a set of possible reactance numbers (dependent on the wave number).
    Źródło:
    Opuscula Mathematica; 2006, 26, 2; 289-303
    1232-9274
    2300-6919
    Pojawia się w:
    Opuscula Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sound Radiation from a Surface Source Located at the Bottom of the Wedge Region
    Autorzy:
    Szemela, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/176912.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wedge region
    sound pressure
    sound power
    Neumann boundary value problem
    Helmholtz equation
    vibrating piston
    Hankel transform
    Opis:
    Applying rigorous analytical methods, formulas describing the sound radiation have been obtained for the wedge region bounded by two transverse baffles with a common edge and bottom. It has been assumed that the surface sound source is located at the bottom. The presented formulas can be used to calculate the sound pressure and power inside the wedge region. They are valid for any value of the wedge angle and represent a generalization of the formulas describing the sound radiation inside the two and three-wall corner region. Moreover, the presented formulas can be easily adapted for any case when more than one sound source is located at the bottom. To demonstrate their practical application, the distribution of the sound pressure modulus and the sound power have been analyzed in the case of a rectangular piston located at the wedge’s bottom. The influence of the transverse baffle on the sound power has been investigated. Based on the obtained formulas, the behaviour of acoustic fields inside a wedge can be predicted.
    Źródło:
    Archives of Acoustics; 2015, 40, 2; 223-234
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Topological sensitivity analysis for a coupled nonlinear problem with an obstacle
    Autorzy:
    Abdelbari, M.
    Nachi, K.
    Sokolowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/205653.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    topological derivative
    shape optimization
    SteklovPoincaroperator
    Signorini problem
    variational inequality
    Helmholtz equation
    coupled partial differential equations
    conical differential
    asymptotic expansions
    singular perturbations of geometrical Romains
    truncated domain
    Opis:
    The Topological Derivative has been recognized as a powerful tool in obtaining the optimal topology for several kinds of engineering problems. This derivative provides the sensitivity of the cost functional for a boundary value problem for nucleation of a small hole or a small inclusion at a given point of the domain of integration. In this paper, we present a topological asymptotic analysis with respect to the size of singular domain perturbation for a coupled nonlinear PDEs system with an obstacle on the boundary. The domain decomposition method, referring to the SteklovPoincar´epseudo-differential operator, is employed for the asymptotic study of boundary value problem with respect to the size of singular domain perturbation. The method is based on the observation that the known expansion of the energy functional in the ring coincides with the expansion of the Steklov-Poincar´e operator on the boundary of the truncated domain with respekt to the small parameter, which measures the size of perturbation. In this way, the singular perturbation of the domain is reduced to the regular perturbation of the Steklov-Poincar´e map ping for the ring. The topological derivative for a tracking type shape functional is evaluated so as to obtain the useful formula for application in the numerical methods of shape and topology optimization.
    Źródło:
    Control and Cybernetics; 2017, 46, 1; 5-25
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Variational equations on the Möbius strip
    Variační rovnice na Möbiově pásce
    Autorzy:
    Urban, Z.
    Volná, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/113594.pdf
    Data publikacji:
    2017
    Wydawca:
    STE GROUP
    Tematy:
    Lagrangian
    Euler-Lagrange equation
    Helmholtz conditions
    fibered manifold
    Möbius strip
    równanie Eulera-Lagrange'a
    warunki Helmholtza
    wstęga Möbiusa
    Opis:
    In this paper, systems of second-order ordinary differential equations (or dynamical forms in Lagrangian mechanics), induced by the canonical embedding of the two-dimensional Möbius strip into the Euclidean space, are considered in the class of variational equations. For a given non-variational system, the conditions assuring variationality (Helmholtz conditions) for the induced system on the Möbius strip are formulated. The theory contributes to variational foundations of geometric mechanics.
    V tomto clánku je studována variacnost systému obycejných diferenciálních rovnic (dynamických forem v geometrické mechanice) druhého rádu, kterou indukuje kanonické vložení dvojrozmerné Möbiovy pásky do Euklidova prostoru. Pro daný nevariacní systém rovnic jsou formulovány nutné a postacující podmínky variacnosti (Helmholtzovy podmínky). Práce je príspevkem k variacním základum geometrické mechaniky na Möbiove pásce.
    Źródło:
    Systemy Wspomagania w Inżynierii Produkcji; 2017, 6, 4; 325-333
    2391-9361
    Pojawia się w:
    Systemy Wspomagania w Inżynierii Produkcji
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-11 z 11

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