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Showing 1 to 20 of 68 for “"shear layers"”.
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Automated feature extraction of shear layers in CFD simulations
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2002.
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An Experimental Study of Compressible Turbulent Reattaching Free Shear Layers
… two-dimensional, turbulent reattaching free shear layers formed by geometrical separation of a Mach 2.46 and a Mach 2.07 turbulent boundary layer flows over a backward-facing step. In the first set of experiments, the wind tunnel test section was specifically designed to obtain flow …
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Vortex Flows: The Dynamics of Shear Layers and Hill's Vortex
… the nonlinear instability of free vortex layers and Hill's vortex. The evolution is calculated numerically employing the contour dynamics formulation. We show that the growth of small, monochromatic perturbations on unstable vortex layers leads to the development of elliptical vortices …
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Gas dynamic and acoustic interactions with supersonic free shear layers
Experiments were conducted in a two-dimensional wind tunnel to study dynamics of large-scale structures in a planar compressible mixing layer. High-speed cinematic (300,000 frames/sec) Mie-scattering and shadowgraph techniques were employed to track the evolution of these structures in the mixing …
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Numerical modeling and simulation of compressible reacting turbulent shear layers
… simulation of compressible reacting turbulent shear layers are considered. In the numerical modeling portion of this work, improved turbulent transport models for compressible shear layers are presented and validated with detailed experimental data. The new compressible models are one-equation …
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Very large eddy simulations of spatially evolving supersonic turbulent shear layers
… levels of compressibility for supersonic shear flows. Very Large Eddy Simulations (VLES) were performed based on the two-dimensional unsteady Euler equations without any empirical coefficients for turbulence modeling. These equations were used to study the spatially evolving mixing …
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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 image the …
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Effects of Compressibility and Variable-Density on the Instability Growth within Buoyancy-Driven Shear Layers
… on the instability growth within buoyancy-driven shear layers (BSL), which share characteristics with the canonical Rayleigh-Taylor (RT/RTI) and Kelvin-Helmholtz (KH/KHI) instabilities. The 2D simulations are performed in a periodic domain, with alternating columns of high and low density fluids …
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A Study of Compressible Turbulent Free Shear Layers Using Laser Doppler Velocimetry (Supersonic Flow, Mixing, Recirculating)
… two-dimensional planar, turbulent free shear layers formed by the separation of a Mach 2.43 flow over a backward facing step was conducted. Two different wind tunnel test sections were used to achieve a constant pressure separation of the shear layer at the backstep corner so that the …
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Development of Viscous Free Shear Layers Between Two Compressible Constant Pressure Isoenergetic Streams With Special Considerations of Itsdissipative Mechanisms
Made available in DSpace on 2014-12-09T17:13:53Z (GMT). No. of bitstreams: 1 7021009.pdf: 3375611 bytes, checksum: c73ebc4e47482c879ea3028f3a39bf15 (MD5) Previous issue date: 1970
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Characteristics of Coherent Structures in Marine Atmospheric Surface Layer
… coherent structures include ejections, sweeps, shear layers, transverse vortices, and combined events of the shear layers and transverse vortices. Besides these similar coherent structures, there exist the plume and downdraft motions in the unstable marine atmospheric surface layer. It has been …
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An experimental investigation of large-scale structures in supersonic reattaching shear flows
… of large-scale structures within the shear layers, at reattachment, and in the wake region of a supersonic base flow. Single-pulse side and end views were obtained at several streamwise locations to characterize the evolution and three-dimensionality of the large-scale motions. From …
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High Order Explicit Semi-Lagrangian Method for the Solution of Lagrangian Transport and Stochastic Differential Equations
… simulation of chemically, reacting, turbulent shear layers in propulsion systems, this thesis also reports on the stability of the interaction of two cold flow shear layers. Consistent with an explicit, DSEM discretization, the semi-Lagrangian method seeds particles at Gauss quadrature …
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Conditionally Analyzed Mean Velocity and Turbulence Measurements in a Plume-Induced Boundary Layer Separated Flowfield
… (which both peak near reattachment), the primary shear stress, and the normal stress anisotropy. The shock-separated shear layer consists of only a single layer with a large initial growth rate followed by a much smaller growth rate, instead of the two layers found in rapidly expanded shear …
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Experimental and Mathematical Modeling of the Interaction of a Perturbed Free Shear Layer With a Flat Plate
… the upstream effects of the impingement of shear layers on a solid boundary located in the linear region of the shear layer is developed. The model is compared with experimental results. The experimental results and the model suggest that the oscillations that are most amplified are those …
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Vorticity shedding over two-dimensional bodies
… concentrated on the separation region, the free-shear layers and the wake downstream of these bodies. Two inviscid vortex models were developed to predict two different flow phenomena, namely the separated flow over a circular cylinder started impulsively from rest and propagating stall over a …
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Analytical and experimental investigation of a turbulent mixing layer of different gases in a pressure gradient
… this was confirmed experimentally for turbulent shear layers between streams of helium and nitrogen. The only case for which similarity is possible is described. The experimental investigation was conducted in a facility designed to produce turbulent flows at pressures up to 10 atmospheres. …
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Experimental Measurements of Pressure, Temperature, and Density Using High-Resolution N(2) Coherent Anti-Stokes Raman Scattering
… the existence of concentric inner and outer shear layers. The former evolves from a slip line that separates the subsonic inner jet fluid from the surrounding annulus of supersonic fluid. Similarly, the existence of counter-rotating streamwise-oriented vortices may explain the slight …
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