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Wyszukujesz frazę "impedance boundary conditions" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
A Rough Estimation of Acoustics of the Cuboidal Room with Impedance Walls
Autorzy:
Kocan-Krawczyk, A.
Brański, A.
Powiązania:
https://bibliotekanauki.pl/articles/177714.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fourier analysis
room acoustics
absorption coefficient
boundary-value problem
impedance boundary conditions
Opis:
The cuboidal room acoustics field is modelled with the Fourier method. A combination of uniform, impedance boundary conditions imposed on walls is assumed, and they are expressed by absorption coefficient values. The absorption coefficient, in the full range of its values in the discrete form, is considered. With above assumptions, the formula for a rough estimation of the cuboidal room acoustics is derived. This approximate formula expresses the mean sound pressure level as a function of the absorption coefficient, frequency, and volume of the room separately. It is derived based on the least-squares approximation theory and it is a novelty in the cuboidal room acoustics. Theoretical considerations are illustrated via numerical calculations performed for the 3D acoustic problem. Quantitative results received with the help of the approximate formula may be a point of reference to the numerical calculations.
Źródło:
Archives of Acoustics; 2018, 43, 2; 227-233
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Impedance Boundary Conditions applied to solving nonlinear electrodynamic systems
Autorzy:
Pawłowski, S.
Plewako, J.
Powiązania:
https://bibliotekanauki.pl/articles/141489.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nonlinear electrodynamics
Surface Impedance Boundary Conditions
harmonic fields
quasi-stationary fields
skin effect
Opis:
The paper presents a method for solving electromagnetic field problems by applying impedance boundary conditions for systems including conducting bodies of nonlinear magnetic properties in an excited harmonic field. Three types of impedance boundary conditions were derived. A procedure for computing surface impedance based on the transfer matrix is proposed. This procedure has been tested by comparing computational results to calculations where time function distortions were considered, and to the experimental data.
Źródło:
Archives of Electrical Engineering; 2017, 66, 2; 433-446
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Transverse Acoustic Flow on the Input Impedance of Rapidly Flaring Horns
Autorzy:
Nederveen, C. J.
Powiązania:
https://bibliotekanauki.pl/articles/177015.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
input impedance
horn
wind musical instruments
boundary conditions
Opis:
In slowly flaring horns the wave fronts can be considered approximately plane and the input impedance can be calculated with the transmission line method (short cones in series). In a rapidly flaring horn the kinetic energy of transverse flow adds to the local inertance, resulting in an effective increase in length when it is located in a pressure node. For low frequencies corrections are available. These fail at higher frequencies when cross-dimensions become comparable to the wavelength, causing resonances in the cross-direction. To investigate this, the pipe radiating in outer space is modelled with a finite difference method. The outer boundaries must be fully absorbing as the walls of an anechoic chamber. To achieve this, Berenger’s perfectly matched layer technique is applied. Results are presented for conical horns, they are compared with earlier published investigations on flanges. The input impedance changes when the largest cross-dimension (outer diameter of flange or diameter of the horn end) becomes comparable to half a wavelength. This effect shifts the position of higher modes in the pipe, influencing the conditions for mode locking, important for ease of playing, dynamic range and sound quality.
Źródło:
Archives of Acoustics; 2011, 36, 3; 533-544
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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