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.
Results
Showing 1 to 12 of 12 for “"Underexpanded"”.
-
Experimental investigation of particle-laden underexpanded jet flow
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-08-01
-
An investigation of highly underexpanded exhaust jets impinging normal to a curved surface
An experimental investigation of highly underexpanded exhaust jets impinging in a direction normal to a curved surface was conducted in the NASA-Langley Research Center 55-foot vacuum cylinder. The investigation included measurements of impingement pressures and measurements of various normal shock …
-
The fluid-structure interaction of an axisymmetric underexpanded jet flowing across an adjacent compliant surface
… of the relatively little-explored problem of an underexpanded axisymmetric jet flowing across an adjacent parallel surface, in both rigid-surface and compliant-surface configurations. To date, the vast majority of the literature for both the rigid- and compliant-surface cases has been generated …
-
High speed geological boundary layer flows
… eruption of 1980 which was hypothesized to be an underexpanded jet originally by Kieffer. Key questions include: What causes the transition that can be seen in the two blast zones of Mount St. Helens characterized by the blow down pattern of the trees? On the double-ejecta layer craters, what …
-
Experimental Measurements of Pressure, Temperature, and Density Using High-Resolution N(2) Coherent Anti-Stokes Raman Scattering
In the underexpanded jet flowfield, the experimental P/T/p measurements are compared to similar quantities extracted from a RANS CFD simulation. The agreement between the mean CARS measurements and CFD predictions along the jet centerline and radial traverses is generally excellent. This CARS …
-
Experimental and computational investigation of helium injection into air at supersonic and hypersonic speeds
… number of 5.0 x 107 1m. was a single. sonic. 5X underexpanded, helium jet at a downstream angle of 30° relative to the freestream. This injector was rotated from 0° to _28° to test the effects of injector yaw. The second model was an array of three supersonic, 5X underexpanded helium injectors …
-
A comprehensive analysis of natural gas direct injection and of mixture formation in spark ignition engines
… Firstly the theoretical background of supersonic underexpanded jets is summarized (section 2.1), followed by a literary review of previous investigations regarding the numerical simulation of gaseous direct injection in internal combustion engines (section 2.2). In section 2.3, the test case of a …
-
New efficient contact discontinuity capturing techniques in supersonic flow simulations
… shear layer problem, triple point problem and underexpanded nozzle flow. Underexpanded nozzle flow involves complex interaction of free surface, shock waves and slip lines. Traditional high-order schemes smear the contact surfaces preventing accurate definition of the flow structure inside the …
-
Oscillating shock impingement on low-angle gas injection into a supersonic flow
… frequencies on a 15° downstream angled, underexpanded, sonic helium jet injected into a supersonic airflow. Information on mixing, penetration, total pressure loss and turbulence structure from these experiments was used to estimate mixing control achieved by adding an oscillating shock …
-
Experimental investigation of helium injection at a low downstream angle into supersonic flow
… enhance large scale mixing. The jet cores of the underexpanded jets had bifurcated 20 jet diameters downstream of the injection point, but had re-united by the 40 diameter station. Wandering of the jet core about the geometric centerline was observed for all cases. The decay rates increased …
-
CFD simulation of flow fields associated with high speed jet impingement on deflectors
Computational Fluid Dynamics is used to analyze the formation of under-expanded jets and to investigate the three-dimensional flow field associated with the impingement of free jets onto stationary deflectors. This investigation was performed to develop a verified modeling ability for such …
-
Fundamental physics and application of plasma actuators for high-speed flows
… investigation of flow control on a sonic underexpanded jet injected normally into a Mach 2.45 crossflow is reported. The jet exit geometry was circular and was operated at a jet-to-crossflow momentum flux ratio of 1.7. The unperturbed flow field was analyzed with schlieren imaging, PIV …