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 28 for “"shock-structure"”.
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Numerical Study of the Stability of Embedded Supersonic Compressor Stages
… UEET compressor and its relation to the rotor shock structure in the relative velocity reference frame. The computational study was conducted with the NASA code ADPAC , utilizing the mixing-plane assumption for the boundary condition between adjacent, relatively-rotating blade rows. A steady, …
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Experimental investigation of noise reduction in supersonic jets due to jet rotation and to nozzle geometry changes
… This component was found to affect the structure of the jet cell and the internal oblique shocks formed inside. In the second method, the nozzle exit plane of the cylindrical chamber was perturbed such that the nozzle's exit lip was not lying in one plane perpendicular to the axis of …
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Experimental and numerical investigation of transonic turbine cascade flow
… needed for the mass averaging and the probe bow shock correction were obtained by pressure taps on the cascade tunnel side wall. The static pressure was also measured on the surface of some instrumented blades. Shadowgraph pictures were taken for study of the trailing edge shock structure and for …
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On the formation of Friedlander waves in a compressed gas driven shock tube
Compressed gas driven shock tubes have become popular as a laboratory-scale replacement for field blast tests. The well-known initial structure of the Riemann problem eventually evolves into a shock structure resembling a Friedlander wave. In this thesis, we develop an analytical model to predict …
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Self-Similar Models of Quasar Outflow Shock Structures
… systems; such winds may drive an expanding shock structure that shocks and pushes the ambient interstellar medium (ISM) outward. This thesis analyses, combines and expands on existing analytic self-similar models of these structures in the context of quasar accretion disk winds; we then …
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Development of the Pressure-Sensitive-Paint Technique for Advanced Turbomachinery Applications
… operating at its peak-efficiency condition. The shock structure is clearly visible in the pressure image, and visual comparison to the corresponding computational fluid dynamics (CFD) prediction shows qualitative agreement to the PSP data.
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Wake closure conditions in plug nozzle flowfields
… The design of the nozzle involves complex wake structures that directly affect engine performance. In particular, the closed or open wake condition of the flow determines the dependence of the base pressure on the ambient environment, and therefore affects overall thrust. An experimental, …
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Shock estimation in supersonic vehicles
… low order model for the estimation of the shock structure generated by vehicles flying in the supersonic and hypersonic regimes. Taking as inputs the geometry and the flow conditions, the proposed approach addresses, in one cohesive methodology, attached and detached shocks in two and three …
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Computational Fluid Dynamics-Informed Analysis of Diaphragm-Free Shock Tubes and Insert Designs
… simulation of a novel, compact, diaphragm-free shock tube is presented using computational fluid dynamics (CFD) in ANSYS Fluent 2022 R1 to better understand shock tube behavior for improved control in high-pressure, high-temperature shock experiments. The study quantifies geometric and viscous …
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A modified Baldwin-Lomax turbulence model for turbomachinery wakes
… of the Baldwin-lomax (Bl) turbulence model for shock/shear layer interactions, reversed flow, and curved, asymmetric wakes is made. No general definition for reference line is available for wakes, and difficulties exist for length scale prediction in complex flows. An entropy envelope for shear …
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Shock formation in overexpanded flow: a study using the hydraulic analogy
Tests were performed to study the mechanism of shock formation in supersonic flow in long orifices to gain insight into the leakage flow of turbine tip gaps. The flow was modeled on a water table using a sharp-edged rectangular channel. The hydraulic analogy between free surface water flows and …
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Detonation modelling of non-ideal high explosives
… a detonation; a supersonic wave consisting of a shock wave coupled to chemical energy release. Detonations in conventional HE (CHE) propagate with a typical velocity of 6 - 8 km/s. Insensitive HE (IHE) and non-ideal HE (NIHE) are of particular interest as they are harder to initiate and thus …
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Dynamics of an Electrodynamic Tether System in a Varying Space-Plasma Environment
… throughout a LEO orbit. The azimuthal current structures observed during the TSS-1R mission are found to enhance the current collected by the satellite when the magnetic field is slightly off of perpendicular to the orbital velocity. When the in-plane component of the magnetic field becomes …
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Modeling of non-equilibrium effects on a double wedge configuration in hypersonic flows
… differences are observed in the heat flux or the shock structure configuration in the air and nitrogen cases.
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Characterization and Analysis of Supersonic Flow Through De Laval Nozzles at Varied Design Conditions
… including internal separation and a well-defined shock structure. Decreasing the operating nozzle pressure ratio led to increased separation shock strength and more significant effects of overexpansion on nozzle performance and thrust capability. The shock interactions with the separated shear …
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An Investigation of Controlled Oscillations in a Plasma Torch for Combustion Enhancement
… device that will produce an oscillating shock and resulting control of the supersonic combustion process. This research will capitalize on previous results [Gallimore, 1998] which indicate that the plasma torch oscillations originate from the inherent oscillations of the voltage applied …
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CFD Performance of Turbulence Models for Flow from Supersonic Nozzle Exhausts
… standard eddy-viscosity models can capture the shock structure and shear layer of the plume accurately when the thickness of the shear layer is small compared to plume diameter. However, when thickness of the shear layer is relatively large, a compressibility correction should be implemented to …
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Polarized Bow Shock Nebulae Reveal Features of the Winds and Environments of Massive Stars
… and ISM is supersonic, then a stellar wind bow shock is formed. Bow shocks and related density enhancements produced by the winds of massive stars moving through the interstellar medium provide important information regarding the motions of the stars, the properties of their stellar winds, and …
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Measurements of Scalar Convection Velocity in Heated and Unheated High-Speed Jets
… imaging is used as a qualitative tool to locate shock cells within the jet plume. TR-DGV data from near the lipline (r = 0.5D) is axially aligned with the shadowgraph images to demonstrate that the shock structure within the potential core causes detectable variations in the scalar convective …
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Shock Wave Dispersion in Weakly Ionized Gas
… to perform additional experimental studies on shock wave modification in non-equilibrium weakly ionized gases and to clarify the physical mechanisms of the shock wave modification process. The discharge was generated in 99.99% Ar at a gas pressure between 20 and 100 Torr and at a discharge …
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