Schallabsorption und -dispersion in Gasen

Kneser, Hans O.

doi:10.1007/978-3-642-45956-6_2

Cited by 6 publications

(4 citation statements)

References 141 publications

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“…F u rth erm o re, diffusion and the internal relaxation o f the gas or the fluid should be considered if com parison w ith accurate m easurem ents is in ten d ed [8], All these ex tensions can be done w ith m eth o d s presented in the ap p en d ix and pro d u ce not m ore difficulties than a larger am o u n t o f w riting.…”

Section: G) Propagation Of Soundmentioning

confidence: 99%

Linear Analysis of the Currents in a Pipe

Brösa

1986

Zeitschrift Für Naturforschung A

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A simple procedure to find solutions o f the hydrodynam ic Stokes equations is given. The procedure is used to determine the linear modes of a newtonian fluid in a pipe of circular cross section. Compressibility, shear and bulk viscosity are included, and no restrictions on the sym metry of the modes are made. Furtherm ore an infinite set o f exact solutions of the Navier-Stokes equations is presented.

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Section: G) Propagation Of Soundmentioning

confidence: 99%

Linear Analysis of the Currents in a Pipe

Brösa

1986

Zeitschrift Für Naturforschung A

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“…Note that the angles a 1 and a 2 are related to the wave normal in the medium 1 and 2, respectively. Other atmospheric in¯uences, like changes of the sound pressure level caused by scattering of the sound waves on temperature inhomogeneities and turbulence elements, as well as the damping in consideration of air absorption, amount to about 0.01 dB for the used frequency range between 500¼1000 Hz, and sourcereceiver distances between 75...230 m, according to numerous authors (Tatarskii, 1961;Kneser, 1961;Aubry et al, 1974;Daigle et al, 1978;Bass, 1981). Therefore, these processes can be neglected for our travel time measurements with a 110 dB-sounder and ray paths up to 230 m.…”

Section: Theoretical Bases Of Sound Propagation In the Atmospherementioning

confidence: 96%

Acoustic tomography in the atmospheric surface layer

1999

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Abstract. Acoustic tomography is presented as a technique for remote monitoring of meteorological quantities. This method and a special algorithm of analysis can directly produce area-averaged values of meteorological parameters. As a result consistent data will be obtained for validation of numerical atmospheric micro-scale models. Such a measuring system can complement conventional point measurements over different surfaces. The procedure of acoustic tomography uses the horizontal propagation of sound waves in the atmospheric surface layer. Therefore, to provide a general overview of sound propagation under various atmospheric conditions a two-dimensional ray-tracing model according to a modified version of Snell's law is used. The state of the crossed atmosphere can be estimated from measurements of acoustic travel time between sources and receivers at different points. Derivation of area-averaged values of the sound speed and furthermore of air temperature results from the inversion of travel time values for all acoustic paths. Thereby, the applied straight ray two-dimensional tomographic model using SIRT (simultaneous iterative reconstruction technique) is characterised as a method with small computational requirements, satisfactory convergence and stability properties as well as simple handling, especially, during online evaluation.Key words. Meteorology and atmospheric dynamics (turbulence; instruments and techniques).

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“…In Bild 11 ist die Konzentrationsabhängigkeit für das Gemisch Kr-He aufgetragen. Dabei zeigt die strichlierte Kurve die "klassische" Absorption [7], Auch bei der Messung der Schallabsorption wird man mit größeren Ungenauigkeiten zu rechnen haben, da Wandlereigenschaften, Reflexion an den Kammerwänden, wie auch das Auftreten stehender Wellen wesentlich stärker in das Meßergebnis eingehen als bei der Messung der Schallgeschwindigkeit. Trotz dieser Schwierigkeiten ist zu erwarten, daß Untersuchungen in dieser Richtung noch einige interessante Zusammenhänge theoretisch wie auch experimentell erbringen werden, zumal auf diesem Gebiet praktisch überhaupt noch nicht gearbeitet wurde.…”

Section: Akustische Gasanalyse Im Vergleich Mit Herkömmlichen Analyseunclassified

Akustische Gasanalyse durch Messung der Schalldispersion, Teil II – Meßverfahren

Goecke¹

1971

tm - Technisches Messen

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Schallabsorption und -dispersion in Gasen

Cited by 6 publications

References 141 publications

Linear Analysis of the Currents in a Pipe

Linear Analysis of the Currents in a Pipe

Acoustic tomography in the atmospheric surface layer

Akustische Gasanalyse durch Messung der Schalldispersion, Teil II – Meßverfahren

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