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 20 of 33 for “"Mixing Layers"”.
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Large eddy simulation of subsonic mixing layers
… the large-scale structures in a low subsonic mixing layer and their breakdown to small scales. For 3-D simulations, different finite-difference and pseudo-spectral schemes are tested. The (2, 4) MacCormack Scheme developed by Gottlieb and Turkel (1976) shows the best overall performance. It is …
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Growth Suppression in Simulated Compressible Turbulent Mixing Layers
Direct numerical simulations of turbulent flows require numerical schemes with high resolution and grid flexibility. Resolution properties of B-spline and compact finite-difference schemes are evaluated using Fourier analysis in periodic domains, and tests based on solution of the wave and heat …
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An experimental investigation of compressible, turbulent mixing layers
An investigation of compressible, turbulent mixing layers has been completed. The experiments were conducted using pressure measurements, schlieren photography and velocity measurements with a two-component laser Doppler velocimeter system. These diagnostic systems were developed for use with the …
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Mixing layers and coherent structures in vegetated aquatic flows
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
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Large eddy simulation of turbulent vortices and mixing layers
… turbulent structures of vortices and free shear layers. The recently developed dynamic model and the basic Smagorinsky model are utilized to model the subgrid-scale(SGS) stress tensor. The dynamic model has many advantages over the existing SGS models. This model has the ability to vary in time …
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Centrifugal instability of the wake dominated curved compressible mixing layers
… which is aligned with the centreline of a curved mixing layer system. The Görtler modes were previously found to exist within the curved compressible mixing layers by Owen et al. (1997). This study extends the work of Owen et al. (1997) and attempts to demonstrate the effect a wake has on the …
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On the turbulence-generated sound and control of compressible mixing layers
"A mixing layer is a common model used to study the noise generation and mixing characteristics of the near-nozzle region of jets. This work presents three separate but related studies that investigate sound generation and active control for noise mitigation and mixing enhancement of such mixing …
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On the Growth Rate of Turbulent Mixing Layers: A New Parametric Model
… model for the growth rate of turbulent mixing layers is proposed. A database of experimental and numerical mixing layer studies was extracted from the literature to support this effort. The domain of the model was limited to planar, spatial, nonreacting, free shear layers that were not …
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Compressibility effects on large-scale structures and entrainment in turbulent planar mixing layers
In this work, experiments on planar free shear layers are conducted to obtain a set of benchmark computational fluid dynamics-validation data and to examine compressibility effects on shear layer turbulence. Five different dual-stream air mixing layers are studied, with levels of compressibility …
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Numerical Investigation using RANS Equations of Two-dimensional Turbulent Jets and Bubbly Mixing layers
… single-phase turbulent jets and bubbly mixing layers using Reynolds-Averaged Navier-Stokes (RANS) equations. The behavior of a turbulent jet confined in a channel depends on the Reynolds number and geometry of the channel which is given by the expansion ratio (channel width to jet …
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Design and development of a wind tunnel for the investigation of turbulent compressible mixing layers
… benchmark experimental data of the compressible mixing layer phenomenon for use in computational fluid dynamics (CFD) validation. This need has arisen because of improved computational capability and the practicality of high-resolution flow simulation techniques of the turbulent compressible …
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Wavelet Analysis and its Application to Modulation Characterization
… and its application to steady and unsteady mixing layers is discussed. Modulation effects are demonstrated by using the magnitude and phase of the wavelet coefficients. The time-varying characteristics of the most unstable modes are determined using the real part of the wavelet coefficients. …
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Control of the abyssal ocean overturning circulation by mixing-driven bottom boundary layers
… circulation is driven by bottom-enhanced mixing, which results in vigorous upwelling in the bottom boundary layer (BBL) along the sloping seafloor and downwelling in the stratified mixing layer (SML) above; their residual is the overturning circulation. This boundary-controlled circulation …
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Control of the abyssal ocean overturning circulation by mixing-driven bottom boundary layers
… circulation is driven by bottom-enhanced mixing, which results in vigorous upwelling in the bottom boundary layer (BBL) along the sloping seafloor and downwelling in the stratified mixing layer (SML) above; their residual is the overturning circulation. This boundary-controlled circulation …
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Momentum and scalar transport in vegetated shear flows
… of submerged vegetation on the hydrodynamics and mixing processes in aquatic flows remains poorly understood. In this thesis, I present the results of laboratory experiments that describe the salient hydrodynamic and transport features of vegetated flows. Flume experiments were conducted with …
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On the structure of laminar diffusion flames
… reaction rates. For large Reynolds numbers mixing and combustion take place in boundary layers and free mixing layers. And again analytical solutions are obtained for the tempera ture and mass fraction distributions outside of the reaction zone.
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An experimental investigation of organized structure and mixing in compressible turbulent free shear layers
… characteristics of compressible turbulent mixing layers have been experimentally investigated at various levels of compressibility in order to study the fundamental effects of compressibility on the nature of the mixing layer. Nonintrusive optical diagnostic techniques were employed to …
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A New Two-Scale Decomposition Approach for Large-Eddy Simulation of Turbulent Flows
… flows, including forced isotropic turbulence, mixing layers and well-developed channel flow, and demonstrated good capabilities to capture turbulent flow features using relatively coarse grids.
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Aspirating probes for measurement of mean concentration and fluctuating quantities in supersonic air/helium shear layer
… make measurements in supersonic air/helium shear layers. The first probe is designed to measure local mean gas composition and is referred to as the mean concentration probe. This probe consists of a constant temperature hot-film sensor operating in a channel with a choked exit. The flow over the …
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