Computer Optical Tomography for Fluid Flow Diagnostics PDF Download

Author: Joy M. Abi-Samara
Publisher:
ISBN:
Category :
Languages : en
Pages : 176

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Author: P. Buchhave
Publisher: Springer Science & Business Media
ISBN: 1489912711
Category : Science
Languages : en
Pages : 387

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The origin of optical methods for fluid flow investigations appears to be nontraceable. This is no matter for surprise. After all seeing provides the most direct and common way for humans to learn about their environment. But at the same time some of the most sophisticated methods for doing measurements in fluids are also based on light and often laser light. A very large amount of material has been published in this area over the last two decades. Why then another publication? Well, the field is still in a state of rapid development. It is characterised by the use of results and methods developed within very different areas like optical physics, spectroscopy, communication systems, electronics and computer science, mechanical engineering, chemical engineering and, of course, fluid dynamics. We are not aware of a book containing both introductory and more advanced material that covers the same material as presented here. The book is the result of a compilation and expansion of material presented at a summer school on Optical Diagnosticsfor Flow Processes,held at RiS0 National Laboratory and the Technical University of Denmark in September 1993. The aim of the course was to provide a solid background for understanding, evaluating, and using modem optical diagnostic methods, addressing Ph. D. students and researchers active in areas of fluid flow research. The disciplines represented by the participants ranged from atmospheric fluid dynamics to biomedicine.

Author: Soyoung S. Cha
Publisher: SPIE-International Society for Optical Engineering
ISBN:
Category : Science
Languages : en
Pages : 752

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Author: S. S. (eds.). Cha
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Qian Wang
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Imaging based optical diagnostics have played an important role in combustion and fluids studies. However, most imaging techniques are two dimensional. The increasing interest in accurate whole field measurement has heightened the need for developing three dimensional methods. Furthermore, many flows are inherently 3D in nature. One aim of this study is to develop an innovative 3D schlieren/shadowgraph system based on conventional schlieren/shadowgraph techniques. Furthermore, several research issues related to fluid mechanics and combustion are investigated using multi optical methods, including high speed direct/schlieren imaging, stereo imaging and 3D reconstruction and PIV techniques, etc. Firstly, a stereoscopic shadowgraph system has been developed using two sets of conventional z-type schlieren configurations. The test volume is set at the intersection of two inclined converging beams formed by two pairs of parabolic mirrors. Two synchronised high speed cameras are used to record the shadowgraph image pairs simultaneously. A precisely etched metal mesh plate is used to calibrate the stereoscopic shadowgraph system. The fully developed MATLAB code is employed to obtain calibration parameters and 3D coordinates reconstruction. A crystal block with internal 3D images is acted as a static model for point reconstruction. The 3D coordinates obtained are in good agreement with the real dimensions. The technique has been subsequently applied to investigate the bursting dynamics of a bubble. The 3D curve reconstruction is also accomplished successfully. The stereoscopic shadowgraph technique has been shown to be an effective method for both 3D visualisation and quantitative measurement. Secondly, the spark induced hot gas jet of a gas turbine combustor igniter has been investigated using optical methods with the combination of high speed schlieren and stereo imaging. A spherical shockwave and a hot gas jet are observed after spark initiation. The 3D velocity vectors of the flying off metal bits are calculated by a stereo imaging and reconstruction algorithm. It has been found that the amount and velocity distributions of the eroded metal bits are very different even at a fixed input voltage to the igniter, which contrasts with the quite consistent hot gas jet development. The 3D structures of the interaction boundaries between hot gas and ambient air are reconstructed for the first time using stereoscopic shadowgraph technique. Thirdly, the vortex dynamics and structures of methane-air diffusion flames are investigated under different co-flow conditions. The schlieren and PIV images show that the visible flame flickering is dominated by the dynamics of the external toroidal vortices outside. The co-flow air is observed to push the initiation point of toroidal vortices beyond the visible flame height and suppress flame flickering completely. The velocity vectors and vorticity contours at different air flow rates are presented and analysed. The shedding frequency of the toroidal vortex is found to be consistent with the result obtained from a photomultiplier. The investigation indicates that co-flow helps to depress flame instability by changing the vortex evolution. Finally, a laminar diffusion flame is studied under external acoustic excitation at different frequencies (6 Hz-100 Hz). The flame structures and vortex evolutions are investigated using high-speed stereo/schlieren imaging and digital imaging processing techniques. The flame frequency shows obvious nonlinear response to both the excitation frequency and amplitude. Several typical nonlinear phenomena were observed and analysed, which may serve as proof for relevant numerical simulation.

Author: Soyoung S. Cha
Publisher: SPIE-International Society for Optical Engineering
ISBN:
Category : Science
Languages : en
Pages : 426

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Author: Xiao-Xia Yin
Publisher: Springer
ISBN: 3319570277
Category : Computers
Languages : en
Pages : 229

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This book presents advances in biomedical imaging analysis and processing techniques using time dependent medical image datasets for computer aided diagnosis. The analysis of time-series images is one of the most widely appearing problems in science, engineering, and business. In recent years this problem has gained importance due to the increasing availability of more sensitive sensors in science and engineering and due to the wide-spread use of computers in corporations which have increased the amount of time-series data collected by many magnitudes. An important feature of this book is the exploration of different approaches to handle and identify time dependent biomedical images. Biomedical imaging analysis and processing techniques deal with the interaction between all forms of radiation and biological molecules, cells or tissues, to visualize small particles and opaque objects, and to achieve the recognition of biomedical patterns. These are topics of great importance to biomedical science, biology, and medicine. Biomedical imaging analysis techniques can be applied in many different areas to solve existing problems. The various requirements arising from the process of resolving practical problems motivate and expedite the development of biomedical imaging analysis. This is a major reason for the fast growth of the discipline.

Author: United States. National Bureau of Standards
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 784

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Author: Clive Greated
Publisher: John Wiley & Sons
ISBN: 9781860582813
Category : Science
Languages : en
Pages : 328

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Optical methods are now used routinely for the measurement of velocity, concentration, temperature, and other parameters in wide-ranging areas of industrial research and design such as IC engines, turbines, and combustors. Recent advances such as the use of high-resolution CCD cameras and the extension of flow mapping to three dimensions, make optical tools such as particle image velocimetry increasingly viable for use in the industrial environment. This excellent book presents new developments in optical diagnostic techniques in heat and fluid flow and offers an unparalleled opportunity for industrialists and academic researchers to exchange ideas. CONTENTS INCLUDE: Comparison of injector sprays for gasoline direct-injection engines The design, development, and preliminary results from a high-speed, optically accessed, single cylinder engine The reflected spectrum of complex multi-layered inhomogeneous highly scattering medium Development of full volume digital holography for particle measurement Improved liquid crystal thermography by using true-colour image processing technology Development of an optical measuring technique for the study of acoustical phenomena Spatio-temporal reconstruction of the unsteady wake of axisymmetric bluff bodies via time-recording DPIV Application of particle image velocimetry to helicopter vortex interactions Pulsed laser particle image velocimetry using a fibre-optic delivery system Automated fringe analysis for profilometric mass-transfer experiments.

Author: Patrick V. Farrell
Publisher: SPIE-International Society for Optical Engineering
ISBN: 9780819450647
Category : Flow visualization
Languages : en
Pages : 0

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