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dc.contributor.advisorTinney, Charles Edmund, 1975-
dc.creatorFiévet, Romainen
dc.date.accessioned2014-09-05T19:48:57Zen
dc.date.issued2014-08en
dc.date.submittedAugust 2014en
dc.identifier.urihttp://hdl.handle.net/2152/25780en
dc.descriptiontexten
dc.description.abstractThe spatial evolution of acoustic waveforms produced by a Mach 3 jet are investigated using both 1/4 inch and 1/8 inch pressure field microphones located along rays emanating from the post potential core where the peak sound emission is found to occur. The measurements are acquired in a fully anechoic chamber where ground, or other large surface reflections are minimal. The calculation of the OASPL along an arc located at 95 jet diameters using 120 planar grid measurements are shown to collapse remarkably well when the arc array is centered on the post potential core region. Various statistical metrics, including the quadrature spectral density, number of zero crossings, the skewness of the pressure time derivative and the integral of the negative part of the quadrature spectral density, are exercised along the peak emission path. These metrics are shown to undergo rapid changes within 2 meters from the source regions of this laboratory scale jet. The sensitivity of these findings to both transducer size and humidity effects are discussed. A visual extrapolation of these nonlinear metrics toward the jet shear layer suggests that these waveforms are initially skewed at the source. An experimentally validated wave packet model is used to confirm the location where the pressure decay law transition from cylindrical to spherical. It is then used to estimate the source intensity, which is required to predict the effective Gol'dberg number.en
dc.format.mimetypeapplication/pdfen
dc.language.isoenen
dc.subjectSupersonicen
dc.subjectAcousticen
dc.titleAcoustic waveforms produced by a laboratory scale supersonic jeten
dc.typeThesisen
dc.date.updated2014-09-05T19:48:57Zen
dc.description.departmentAerospace Engineeringen
thesis.degree.departmentAerospace Engineeringen
thesis.degree.disciplineAerospace Engineeringen
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Science in Engineeringen


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