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3D Noise Source Location using Matched Field ProcessingUmlauft, Josefine 20 February 2019 (has links)
The Matched Field Processing approach is evaluated and was applied in the geophysical context. Synthetic tests were performed using Finite Difference Modelling that show the resolution of the approach considering different environmental setups. Matched Field Processing was applied to two field data sets. On the Hartousov Mofette Field (NW Bohemia/Vogtland region, Czech Republic) it was used to locate subsurface fluid channels and to investigate their spatio-temporal variations. On the Gornergletscher (Canton Valais, Switzerland) it was applied to monitor lake drainage from the ice-marginal lake Gornersee and to locate accompanying water tremor sources.
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Overall Sound Pressure Level Contours of Jet Noise by Cartesian Acquisition GridPerry, Stephen 14 December 2018 (has links)
Noise pollution from aircraft is an ever-increasing issue in urban areas. Venting exhaust over body panels could reduce perceived sound pressure levels (SPL) by absorption or redirection. This paper investigates the farield spectra and sound propagation of a flat panel held near an axis-symmetric supersonic jet. In contrast to typical radial acquisition, Overall sound pressure level (OASPL) contours are constructed from a 9 by 23 cartesian acquisition gird, spaced equidistantly at 3.67 Jet Diameters (Dj). Three panel configurations each at three nozzle pressure ratios (NPR) are discussed. Additionally, a source finding algorithm is developed and shows source locations by frequency. Panel presence for nozzle design conditions result in a near flat increase in SPL across the acquired spectrum, while over and under expanded nozzle cases show the propagation of resonant modes.
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