摘要 :
A review emphasizing the quantitative studies of leading-edge vortices at supersonic speed is presented. While quantitative investigations of vortical flow over delta wings are extensive in the incompressible regime, and to a degr...
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A review emphasizing the quantitative studies of leading-edge vortices at supersonic speed is presented. While quantitative investigations of vortical flow over delta wings are extensive in the incompressible regime, and to a degree in transonic range, their measurements in supersonic freestream are very scarce. It is illustrated that the existing knowledge of leading-edge vortices in the supersonic regime is mainly qualitative, compiled from large amount of flow visualization experiments. A brief account of the flow visualization studies is first presented, followed by a comprehensive survey of the various measurement attempts to quantify these vortices. On the qualitative side, this survey reveals that in spite of the past efforts, the literature still lacks a unified topological description of the compressible leeward vortical Hows. In quantitative investigations, the experience with pressure probes and seed based optical measurement techniques is highlighted, and the associated results summarized. Amongst them, although there exists a topological similarity in the delta wing leeward flow at low- and high-speeds, available measurements suggest that leading-edge vortices in supersonic flow have a very different axial flow character. Additional salient features of leading-edge vortices in supersonic freestreams are also provided in the paper.
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摘要 :
Laser percussion drilling is widely used in the aerospace industry to produce cooling holes in jet engine components. A variety of theoretical models have been developed to predict the outcome of the drilling process. However, to ...
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Laser percussion drilling is widely used in the aerospace industry to produce cooling holes in jet engine components. A variety of theoretical models have been developed to predict the outcome of the drilling process. However, to utilize these models often requires sophisticated software to perform the required numerical analyses. A simple and easy-to-use computer utility Drilling Routine for Estimating, Analyzing, and Modeling (dream) was developed. DREAM is a free-standing MATLAB-based design that offers a convenient and flexible way to predict a variety of drilling process outcomes and can be executed on any Windows-based platform. This paper discusses the features that have been incorporated into the latest release.
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摘要 :
A miniature conical five-hole probe of 30 half-angle was numerically calibrated for measurements of flow properties at supersonic Mach numbers in order to circumvent the traditional experimental approach, vastly demanding on resou...
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A miniature conical five-hole probe of 30 half-angle was numerically calibrated for measurements of flow properties at supersonic Mach numbers in order to circumvent the traditional experimental approach, vastly demanding on resources. The principle of a multi-hole conical probe is based on the notion that Mach number, pressure and directionality of the incoming stream may he correlated with the combination of pressure readings on the conical probe surface and a Pitot port situated at the flat tip. Using a three-dimensional thin layer Navier-Stokes solver, calibration data were generated for the range of Mach numbers and pitch angles of interest. The validity of the computed pressure distributions on the probe surface was subsequently confirmed in a series of wind tunnel tests including low Mach number and high angularity flow-field. The current study also demonstrated the profound influence of the blunt tip on the nearby static pressure ports, its relevance to the ultimate modelling strategy and the resulting calibration charts.
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