Download or read book An Experimental Investigation of Large scale Structures in Supersonic Reattaching Shear Flows written by Kenneth Michael Smith and published by . This book was released on 1996 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-resolved, planar imaging was employed to study the spatial organization of large-scale structures within the shear layers, at reattachment, and in the wake region of a supersonic base flow. Single-pulse side and end views were obtained at several streamwise locations to characterize the evolution and three-dimensionality of the large-scale motions. From statistically significant ensembles, spatial correlation fields were computed to quantify the mean size, eccentricity, and orientation of the large structures. Double-pulse visualizations were also performed to capture an accurate time history of individual structures and to measure the local streamwise convection velocity. Visualizations confirm that large-scale turbulent structures exist at all stations in the shear layers and interact vigorously with the recirculation region. Mach and/or shock waves are frequently seen emanating from within the shear layers which may be indicative of eddy shocklet formation. The embedded turbulent structures are elliptical in shape and usually appear inclined to the mean flow direction. A distinct flattening and tilting in the streamwise direction occurs as the coherent eddies negotiate shear layer formation, recompression, and reattachment processes. Spatial statistics indicate that the structures have a streamwise and spanwise spatial extent on the order of the local shear layer thickness. Examinations of spatial correlation fields suggest that the embedded structures are thoroughly three-dimensional at all streamwise stations. Furthermore, the structures appear to degrade in their spatial organization during the recompression and reattachment processes. Time-correlated images indicate that the individual structures evolve primarily through an elongation and rotation toward the streamwise direction. The structures possess a limited temporal coherence, typically of the order of one eddy roll-over time. Convection velocities near the base are higher than the isentropic prediction, in agreement with previous compressible shear layer studies. During recompression and reattachment, the structures slow considerably, apparently in response to the adverse pressure gradient. Downstream of reattachment, the structures accelerate as the mean flow accelerates.
Download or read book Large scale Structures in Supersonic Re attaching Shear Flows written by K. M. Smith and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of Large Scale Instabilities in a Low Reynolds Number Two stream Supersonic Shear Layer written by Dennis K. McLaughlin and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Resolution Measurements of Supersonic Shear Flow Mixing and Combustion written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An initial experimental study of the effects of compressibility on the outer variable scalings and large-scale structure of a supersonic coflowing turbulent jet operating in the wake-like mode was completed. The results showed that the large-scale structure is clearly evident in the downstream portion of the flow, where the convective Mach number has become subsonic. However the structures appear to be suppressed in the upstream portion of the flow, at supersonic convective Mach numbers. The results also showed that the local flow width and growth rate in the downstream portions of the flow are good in agreement with the scaling laws for the corresponding incompressible flow.
Download or read book Experimental Investigation of Supersonic Cavity Flows and Their Control written by Ning Zhuang and published by . This book was released on 2007 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of supersonic cavity flows is of interest both from fundamental fluid dynamics and practical perspectives. The complex nature of this flowfield, consisting of compressible shear layers, compression/expansion waves, and fluid-acoustic interactions, makes it a rich problem to study. A detailed experimental study of supersonic flow (M=1.5 to 2) over a range of three-dimensional rectangular cavities (L/D=1 to 5.2) was conducted. The measurements included unsteady surface pressure measurements, particle image velocimetry, and flow visualization using shadowgraph and schlieren. Large-scale structures in the shear layer and a large recirculation zone in the cavity was observed. Spatial and temporal mode switching was also observed, the nature being different for short and long cavities. The shear layer characteristics of the two cavities are very different in term of curvature and growth. Supersonic microjets were used at the leading edge of the cavities to suppress the resonance in the flow. With a minimal mass flux (0.15%), the activation of microjets led to a large reduction in cavity tones (20 dB) and overall sound pressure levels (9dB). In addition, the microjet injection enhanced the shear layer mixing and reduced the velocity fluctuation in the cavities. The significant reductions together with the low mass flux requirements make this a potentially viable technique for full-scale, practical applications.
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2006 with total page 1380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Shear Layers in Supersonic Flow written by Alexander J. Smits and published by Springer Science & Business Media. This book was released on 2006-05-11 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: A good understanding of turbulent compressible flows is essential to the design and operation of high-speed vehicles. Such flows occur, for example, in the external flow over the surfaces of supersonic aircraft, and in the internal flow through the engines. Our ability to predict the aerodynamic lift, drag, propulsion and maneuverability of high-speed vehicles is crucially dependent on our knowledge of turbulent shear layers, and our understanding of their behavior in the presence of shock waves and regions of changing pressure. Turbulent Shear Layers in Supersonic Flow provides a comprehensive introduction to the field, and helps provide a basis for future work in this area. Wherever possible we use the available experimental work, and the results from numerical simulations to illustrate and develop a physical understanding of turbulent compressible flows.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 40th AIAA Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 2002 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 43rd AIAA Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 2005 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unsteady Computational Fluid Dynamics in Aeronautics written by P.G. Tucker and published by Springer Science & Business Media. This book was released on 2013-08-30 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of Large Eddy Simulation (LES) and hybrids is a vibrant research area. This book runs through all the potential unsteady modelling fidelity ranges, from low-order to LES. The latter is probably the highest fidelity for practical aerospace systems modelling. Cutting edge new frontiers are defined. One example of a pressing environmental concern is noise. For the accurate prediction of this, unsteady modelling is needed. Hence computational aeroacoustics is explored. It is also emerging that there is a critical need for coupled simulations. Hence, this area is also considered and the tensions of utilizing such simulations with the already expensive LES. This work has relevance to the general field of CFD and LES and to a wide variety of non-aerospace aerodynamic systems (e.g. cars, submarines, ships, electronics, buildings). Topics treated include unsteady flow techniques; LES and hybrids; general numerical methods; computational aeroacoustics; computational aeroelasticity; coupled simulations and turbulence and its modelling (LES, RANS, transition, VLES, URANS). The volume concludes by pointing forward to future horizons and in particular the industrial use of LES. The writing style is accessible and useful to both academics and industrial practitioners. From the reviews: "Tucker's volume provides a very welcome, concise discussion of current capabilities for simulating and modellng unsteady aerodynamic flows. It covers the various pos sible numerical techniques in good, clear detail and presents a very wide range of practical applications; beautifully illustrated in many cases. This book thus provides a valuable text for practicing engineers, a rich source of background information for students and those new to this area of Research & Development, and an excellent state-of-the-art review for others. A great achievement." Mark Savill FHEA, FRAeS, C.Eng, Professor of Computational Aerodynamics Design & Head of Power & Propulsion Sciences, Department of Power & Propulsion, School of Engineering, Cranfield University, Bedfordshire, U.K. "This is a very useful book with a wide coverage of many aspects in unsteady aerodynamics method development and applications for internal and external flows." L. He, Rolls-Royce/RAEng Chair of Computational Aerothermal Engineering, Oxford University, U.K. "This comprehensive book ranges from classical concepts in both numerical methods and turbulence modelling approaches for the beginner to latest state-of-the-art for the advanced practitioner and constitutes an extremely valuable contribution to the specific Computational Fluid Dynamics literature in Aeronautics. Student and expert alike will benefit greatly by reading it from cover to cover." Sébastien Deck, Onera, Meudon, France
Download or read book NBS Special Publication written by and published by . This book was released on 1980 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydraulic Research in the United States and Canada 1978 written by Pauline H. Gurewitz and published by . This book was released on 1980 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1971 with total page 1388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications Cumulative Index written by United States. Superintendent of Documents and published by . This book was released on 1976 with total page 1408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of Shear Layer Mixing in Supersonic Flows written by Gary Alan Sullins and published by . This book was released on 1988 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
