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1

A Rough Estimation of Acoustics of the Cuboidal Room with Impedance Walls

Kocan-Krawczyk A., Brański A.

Archives of Acoustics

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2018

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Vol. 43, No. 2

227--233

EN

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.

2

Applicability assessment for simplified formulas to compute surface impedance at screened surfaces

Pawłowski S., Plewako J.

Przegląd Elektrotechniczny

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2015

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R. 91, nr 12

182-184

EN

It is well known that when determining surface impedance for screened well conducting bodies errors generated due to underestimated curvature radius of the surface occur. This problem is dealt with in the paper, where calculation results for formulas with the screened surface curvature considered and disregarded are compared.

PL

W pracy przeanalizowano zagadnienie błędu popełnianego przy wyznaczaniu impedancji powierzchniowej ekranowanego ciała przewodzącego, spowodowanego założeniem o małej krzywiźnie powierzchni. Porównano rezultaty obliczeń według dwóch wzorów: uwzględniającego i nieuwzględniającego krzywiznę ekranowanej powierzchni.

3

Determination of reduced parameters for the impedance boundary conditions at screened surfaces

Pawłowski S., Plewko J.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 12

257--260

EN

A method for calculating impedance boundary conditions reduced parameters at permeable screen surfaces in a quasi-stationary electromagnetic field is presented. Solving a model, spherically symmetric system allowed to obtain dependencies, determining these parameters as functions of the curvature radius of the screened surface, and material parameters of the screen and the screened area.

PL

W pracy zaproponowano metodę obliczania zredukowanych parametrów impedancyjnych warunków brzegowych na powierzchniach ekranów przenikalnych w quasi-stacjonarnym polu elektromagnetycznym. Na podstawie rozwiązania modelowego zagadnienia o symetrii sferycznej otrzymano zależności pozwalające określić te parametry w zależności od promienia krzywizny powierzchni ekranowanej oraz parametrów materiałowych ekranu i obszaru ekranowanego.

4

Using improved impedance boundary conditions to derive distributions of electromagnetic fields

Apanasewicz S., Pawłowski S.

Journal of Technical Physics

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2000

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Vol. 41, no 2

159-171

EN

In this paper the improved boundary condition of impedance type the harmonic low-frequency electromagnetic field calculation is presented. It is based on the application of successive approximations in two-dimensional case. As an illustration of the presented method the calculation of electromagnetic field in the neighbourhood of metallic wall is given. A comparison of approximate solutions with the exact one is done (Figs. 3-8).