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Showing 1 to 20 of 63 for “"Mixing Layer"”.
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Instabilities of a compressible mixing layer
Instability waves in a free shear layer formed by two parallei compressibie streams are analyzed using the linear spatial stability theory. Both viscous and inviscid disturbances are considered. The basic state is obtained by solving the compressibie laminar boundary-layer equations or is specified …
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A numerical investigation of the compressible mixing layer
The effect of Mach number on the plane muong layer has been investigated by means of linear stability theory and two- and three-dimensional direct numerical simulations of the compressible Navier-Stokes equations. The objective was to identify the effects of compressibility on a building-block …
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Three-dimensional pulsed disturbances in a plane mixing layer.
… evolution of 3-D pulsed disturbances in a plane mixing layer is studied experimentally. The disturbance is effected via amplitude modulation of a spanwise uniform time-harmonic wave train which provides a clear phase reference for the phase-locked velocity measurements. The evolution of the …
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Compressible turbulence in a high-speed high Reynolds number mixing layer
… high Reynolds number, supersonic free shear layer was studied. A two-dimensional free mixing layer was chosen to study turbulence rather than a wall bounded flow due to the experimental fact that the effects of compressibility become significant at lower Mach numbers. The mixing layer was …
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Planar Velocity Measurements in an Incompressible and a Weakly Compressible Mixing Layer
For the weakly compressible mixing layer, the velocity ratio was 0.53, the density ratio was 0.67, and the convective Mach number was 0.38. At the location where the PIV images were obtained, Rex = 3.7 x 106 , Redw = 1.8 x 105, and Rx/lambda = 18. The planar velocity fields obtained in this study …
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Effect of heating on sound radiated from a two-dimensional mixing layer
… by instability waves in a two-dimensional mixing layer is studied. A linear stability theory coupled with linearized Euler calculations are used to compute the amplitude of the instability wave and its associated sound field. The linear stability analysis also identifies the point of …
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Remote Sensing of the Lower Atmosphere: From Surface Concentration to Mixing Layer Height
… method to calculate HCHO near surface volume mixing ratio is presented where radiative transfer modelling is not required. The HCHO near surface volume mixing ratio calculated by MAX-DOAS is compared with surface HCHO measured by a ground in-situ instrument. The Pandora MAX-DOAS agrees very …
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Statistical Investigation of Turbulent Velocity and Pressure Fields in a Two-Stream Mixing Layer
Made available in DSpace on 2014-12-11T17:26:02Z (GMT). No. of bitstreams: 1 7105246.pdf: 6514182 bytes, checksum: 37c92cd1fcbb6653c8dfdfccb819c40e (MD5) Previous issue date: 1970
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Comparison of Two Vortex-in-cell Schemes Implemented to a Three-dimensional Temporal Mixing Layer
… implementing it to a three dimensional temporal mixing layer. Comparisons of the mean flow and velocity statistics are made with experimental studies. The results confirm the validity of the present schemes. Both schemes also demonstrate capability to qualitatively capture significant flow …
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Analytical and experimental investigation of a turbulent mixing layer of different gases in a pressure gradient
… and experimental study was made of the turbulent mixing layer in adverse and zero pressure radients. Theory predicts the possible existence of equilibrium flows, and this was confirmed experimentally for turbulent shear layers between streams of helium and nitrogen. The only case for which …
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Mean-flow measurements of a turbulent mixing layer from helium slot injection into a supersonic airstream
This investigation studies the mixing in a shear layer developed from helium slot injection into a parallel supersonic airstream and compares the results to those of previous slot-injection tests. The objectives of this study include documenting the helium slot-injection flowfield; providing a …
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A computational investigation of the fluid dynamics of a three-dimensional, compressible, mixing layer with strong streamwise vorticity
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1990.
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Gas dynamic and acoustic interactions with supersonic free shear layers
… 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 layer. A covariance algorithm was developed to obtain quantitative information …
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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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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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Incident shock Mach number effects on Richtmyer-Meshkov mixing with simultaneous density and velocity measurements
… The resulting instability and subsequent fluid mixing is measured using simultaneous quantitative Planar Laser-Induced Fluorescence (PLIF) and Particle Image Velocimetry (PIV) for the first time in a Richtmyer-Meshkov Mach number study, while exceptional experimental repeatability allows for …
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Design and development of a wind tunnel for the investigation of turbulent compressible mixing layers
… a new intermittent-blowdown compressible shear layer wind tunnel built at the Gas Dynamics Laboratory (GDL) at the University of Illinois at Urbana-Champaign. The construction of this facility was motivated by the need for high-quality benchmark experimental data of the compressible mixing layer …
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Airborne Multi AXis DOAS instrument and measurements of two-dimensional tropospheric trace gas distributions
… flying either close to the tropopause or in the mixing layer. In a detailed sensitivity study the possibilities of the measurements were investigated. For a qualitatively good observation of tropospheric trace gases (e.g. NO2 and HCHO) additional information about the mixing layer height and the …
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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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Covering Shock Wave Induced Interfacial Mixing: Numerical Study and a Control Primer
… deepening the understanding of the phenomena of mixing and the effect of the initial conditions in the cylindrical & spherical Richtmyer-Meshkov and Rayleigh-Taylor Instabilities. This work is focused on identifying the most energetic structures of the ow in order to define a reduced order model …
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