Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"Wavenumber Spectra"”.
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Space and time scales of low frequency variability in the ocean
… low frequency variability energy in horizontal wavenumber, frequency, vertical mode and geography. We assume horizontal isotropy, Φ(K, ω, η, φ, λ) = 2πKψ(k, l, ω, η, φ, λ), with K designating the amplitude of total horizontal wavenumber. The parameters of Φ(K, ω, η, φ, λ) can be derived from …
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Spectral description of low frequency oceanic variability
… various observations to provide an approximate spectral description of low frequency oceanic variability. Such a spectrum has wide application in oceanography, including the optimal design of observational strategy for the deployment of floats, the study of Lagrangian statistics and the estimate …
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Spectral description of low frequency oceanic variability
… various observations to provide an approximate spectral description of low frequency oceanic variability. Such a spectrum has wide application in oceanography, including the optimal design of observational strategy for the deployment of floats, the study of Lagrangian statistics and the estimate …
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Seismic scattering attributes to estimate reservoir fracture density : a numerical modeling study
… is analyzed using integrated amplitude and spectral attributes that focus on time windows around the base reservoir reflection and the scattered wave coda after the base reservoir reflection. Results from a common shot gather show that when the fracture zones are spaced greater than about a …
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Normalization of Roughness Noise on the Near-Field Wall Pressure Spectrum
… all velocities and roughness sizes. The changing spectral shapes of noise generated by rough surfaces with significantly varying wavenumber spectra make it impossible to scale the produced noise using the proposed inner and outer variable scalings. They use only one a single scaling value for the …
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Space-time Description of Supersonic Jets with Thermal Non-uniformity
… $2 pm 0.5$ dB reductions in peak narrowband spectral sound pressure levels upstream of peak directivity directions for the non-uniform jet compared to a thermally uniform baseline, even for static thrust matched conditions. This reduction is hypothesized to be related to perturbations induced …
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Geoacoustic inversion in laterally varying shallow-water environments using high-resolution wavenumber estimation
… input data to the inversion is the horizontal wavenumber spectrum of a point-source acoustic field. The main thrust of the thesis work concerns extracting horizontal wavenumber content for fully three-dimensionally varying waveguide environments. In this context, a high-resolution …
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Measurements and models of fine-structure, internal gravity waves and wave breaking in the deep ocean
… produces a sharp cutoff in vertical current spectra above the local buoyancy frequency N(z). An internal wave wavenumber-frequency spectral model Ε(α,ω) = E(ω/No)-2 (α./α0)-2 describes vertical current spectra and potential energy to horizontal kinetic energy ratios. The red wavenumer shape …
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Evaluation of GEOSAT data and application to variability of the Northeast Pacific Ocean
… separated from altimeter errors. Mean alongtrack wavenumber spectra of oceanic variability for two GEOSAT arcs were compared with a SEASAT-derived regional spectrum of Fu (1983). Agreement was good, with GEOSAT showing less system noise at short wavelengths, and greater oceanic variability at long …
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Triadic Resonance Instability in finite-width internal gravity wave beams
… rather they manifest as beams that span the wavenumber spectra. With an aim of developing our understanding of the role of TRI in oceanic settings, this thesis focuses on how the instability evolves in finite-width internal wave beams. Experiments have been conducted using a new generation of …
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On the turbulence-generated sound and control of compressible mixing layers
… value we are able to compute. Wavenumber spectra of turbulence energy and pressure show the expected Reynolds number dependence: the two highest Reynolds number simulations show evidence of an inertial range and Kolmogorov scaling at the highest wavenumbers. Far-field pressure …
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Simulation of ionospheric plasma heating experiments in the versatile toroidal facility
… forming a standing wave Airy pattern. Wave spectra produced near reflection are measured using a miniature double probe and microwave receiver along with a fast oscilloscope. This combination is capable of simultaneously measuring spectra in two 250 MHz bands, one near DC and the other near …
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Effects of surfzone wave transformation on swash dynamics
… to show that the shape and magnitude of energy spectra can be largely dependent on processes occurring inside the surfzone. The observations took place on a steep, intermediate beach on the east coast (Tairua Beach), and a low-sloping, dissipative beach located on the west coast of New Zealand …
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Spatio-temporal localization of canonical dynamic stall flow scales across varying Reynolds numbers
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01