V.V.Krizhanovskii, V.V.Krizhanovskii (jr.) Sound field in a piecewise-homogeneous finite cylinder excited by axisymmetrical random load on the boundary |
Acoustic bulletin, Vol. 4 ¹ 4, (2001) |
| The problem of calculation of an acoustic field in a finite piecewise-homogeneous hollow cylinder is considered. It is supposed that the field is induced by axi-symmetric sources situated on an internal wall of the cylinder. On the base of the method of decomposition of the boundary problem solution with respect to eigen-functions of differential operators of the Helmholtz's equation the structure of an acoustic field is determined. The structure of solutions for different variants of matching conditions on the interfaces between the cylinder's layers is analyzed. The rational form of general solution, from the viewpoint of numerical precision, is found. The spectral power density of radial vibrational velocity on the external lateral cylinder wall is calculated for a three-layered model. It is supposed that the field is induced by random pressure pulsations, uncorrelated in space. The spectral characteristics of the observed acoustic field, sensitive to heterogeneities on density and the sound speed, are determined. It is shown that the layered cylinder's heterogeneity on density can be discovered using the data on distribution of the spectral power density of an acoustic field along the cylinder's generatrix. In doing so, the sound field may be formed both by the point sources, and the distributed ones. To determine the layered heterogeneity on the sound speed it is expedient to analyze the data on mutual spectral power density of an acoustic field between the supervision points along the cylinder's generatrix. In this case the field should be formed by the source concentrated nearby the cylinder's end faces. |
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KEY WORDS: finite hollow cylinder, the sound source, the spectral density, correlation, structural heterogeneity |
| TEXT LANGUAGE: Russian |