An experimental investigation of the turbulent boundary layer behind a forward facing step in supersonic flow


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The report presents the results of an experimental study of the effect of a disturbance, produced by a forward facing step, on the turbulent boundary layer in compressible flow. Boundary layer total pressure surveys and direct skin friction measurements were made at six stations on each of two test surfaces. One surface was smooth and the other surface had an 0.080-inch forward facing step. The test stations were all located downstream of the step, the height of which was approximately one-half the smooth surface boundary layer thickness. Data were obtained at Mach Numbers of 2.0, 2.5, 3.0, and 3.5 and the test Reynolds Numbers, based on momentum thickness, ranged from 8,000 to 10,000 approximately. The results of this investigation indicate that the effect of the disturbance, produced by the step on the 'law of the wall' and 'velocity defect law' profiles appears to be negligible from a point approximately 10 flat plate boundary layer thicknesses downstream from the step. (Author).







Heat Transfer in Subsonic Separated Flows


Book Description

This book presents the results of scientific research performed over the past two decades by the authors. The book discusses some issues of separated laminar flows that are of great practical interest for the development of new technologies using microchannel flows, where separation zones can form. Of particular interest is the complex mechanism of flow separation with superimposed high external turbulence. The challenges of finding the optimal location for the cavities and fins on heat exchange surfaces are also considered. This is an important fundamental and practical problem when creating new schemes of efficient heat exchangers in various power plants. A wide class of problems of turbulent flow in tubes with flow separation is considered. These data will be useful in engineering estimates of the thermal–hydraulic efficiency of various heat transfer intensifiers. This book focuses on the analysis of thermal characteristics of separated flows, as well as the possibility of controlling the intensity of heat exchange processes, from the point of view of both their intensification and their suppression.







NASA Technical Paper


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Symposia


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