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Showing 1 to 12 of 12 for “"Unstart"”.
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Mitigating Engine Unstart in Scramjets with Porous Bleeders
… effectiveness of porous bleeders in mitigating unstart phenomena and enhancing isolator effectiveness in a hypersonic scramjet was investigated. Through computational fluid dynamics simulations, the impact of porous bleeder design parameters such as pressure jump coefficient and bleeder size on …
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UNSTEADY PRESSURE MEASUREMENTS IN A SUPERSONIC INLET DURING UNSTART SIMULATIONS
Unsteady pressure behavior during inlet unstart is a critical factor in understanding the performance and stability of supersonic systems. This thesis will investigate the unsteady pressure measurements within a supersonic inlet during unstart. By using a model developed by Ben Nikaido, Kulites …
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Experimental study of flow choking and inlet unstart in an axisymmetric model scramjet
Made available in DSpace on 2018-09-27T16:28:03Z (GMT). No. of bitstreams: 3 BACCARELLA-DISSERTATION-2018.pdf: 11707373 bytes, checksum: 856182803b3b4bbc32de9773806c5add (MD5) LICENSE.txt: 4215 bytes, checksum: 6aa9b4b4beb7f8c687f2f47db1477e87 (MD5) PROQUEST_LICENSE.txt: 4561 bytes, checksum: …
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Computational Analysis of Transient Unstart/Restart Characteristics in a Variable Geometry, High-Speed Inlet
… motion are used to predict and investigate the unstart and restart processes of the inlet as well as the associated hysteresis. Good agreement in the quasi-steady limit with a traditional analysis approach was obtained. However, the new model allows for more detailed, time-accurate information …
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Dynamic characterization and active control of unstarts in a near-isentropic supersonic inlet
… in total pressure is achieved by reducing the unstart-tolerance of the inlet and by an efficient boundary layer control mechanism. Thus the resulting inlet design has reduced stability to unstart in the face of atmospheric and engine-born disturbances, necessitating active control. An active …
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A Numerical Evaluation of Hypersonic Inward-Turning Inlets at Off-Design Conditions
… isolator outflow. Based on the off-design cases, unstart boundaries were estimated. The sensitivity to equilibrium vibrational thermodynamic effects was also evaluated. Grid-independent results were ensured using a systematic grid adaptation approach with relatively modest final mesh size. …
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To start or not to start: that is the question
… determine what effects would cause the tunnel to unstart. Unstarting refers to flow not reaching Mach 6 at the apex of the cone or reflection shocks impinging on the surface of the cone causing undesired flow characteristics. There were three main conclusions that were made from this study, …
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Computational analysis of plasma actuation for control of shock-laden flows in scramjet isolators
… can diminish engine performance and cause unstart, an aerodynamic phenomenon that can have catastrophic consequences. Plasma actuation has emerged as a promising approach to mitigate these adverse effects due to its rapid response time and minimal mechanical complexity. This work …
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Transient Computational Fluid Dynamic Modeling of Baffled Tube Ram Accelerator
… shockwave ahead of it like in a jet engine unstart. It was also found that thicker baffles and closer baffle spacing increased the projectile drag coefficient. Reactive flow phenomena were investigated by first establishing the combustion on the projectile in a smooth bore tube before it …
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Experimental and numerical study of hypersonic aeroelastic intakes
… the intake flowfield response, performance, and unstart characteristics.
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Study of Rubber Damped Skin Friction Gages for Transonic Flight Testing
… repeated runs including the violent start and unstart processes typical of a supersonic, blowdown wind tunnel. Flight tests were performed at NASA Dryden Flight Research Center, with the gage mounted in a plate suspended below an F-15 aircraft. This provided a mildly 3D, turbulent boundary …
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A combined cycle approach to dual-mode scramjet design and analysis
… the impetus and consequence of choking and inlet unstart, and the thrust and fuel efficiencies of an ideal scramjet at various flight conditions and their departure from classical Brayton cycle predictions. This theoretical overview is meant to provide an intuitive technical perspective on …