Download or read book A Study of High Speed Flows Using Advanced Optical Diagnostics written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few years, we have been working on the development of advanced optical diagnostics to be used in high speed flows. Our focus has been on the techniques based on molecular absorption filters. The focus of this report is on the details of a two-component planar measurement that we call Planar Doppler Velocimetry (PDV) technique. A PDV technique was developed and used to measure two components of instantaneous velocity in an ideally expanded, Mach 2, free jet. The technique utilizes a molecular filter as a frequency discriminator and uses two cameras to resolve two components of velocity on a plane that is illuminated by a laser sheet. Careful formation of the laser sheet, proper calibration of the splitter/recombiner imaging system and precise image registration were found to be critical steps in the technique. The velocity measurements obtained with this technique were compared with reference LDV measurements taken in the same flowfield. The mean velocity results were in very good agreement with the reference measurements and the turbulence results captured only the correct trend. A detailed error analysis describes the error sources inherent in the PDV technique. For the current two-component PDV system the estimated uncertainty for the mean velocity was better than +/-5%. Methods to improve the technique are discussed.
Download or read book Advanced Optical Diagnostics in High Speed Flows written by M. Samimy and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of Advanced Optical Diagnostics for the Study of High Speed Flows in Micro Systems written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A program has been initiated to develop and demonstrate the applicability of time-of-flight and Doppler-based optical velocimetry techniques to supersonic micro scale flow fields. In particular, Molecular Tagging Velocimetry (MTV) measurements have been performed, using acetone vapor as a molecular tracer, in the flow produced by a 1 mm diameter, pressure matched, sonic nozzle. Measurements were performed over a static pressure range from approximately equal 1 torr to approximately equal 20 torr. Measurement accuracy is found to be on the order of 5 m/sec at a spatial resolution of order 10 microns. As a compliment to the experimental measurements, a computational program was also initiated which focused on the development of in house Navier - Stokes and Direct Simulation Monte Carlo (DSMC) codes.
Download or read book Optical Diagnostics for Flow Processes written by P. Buchhave and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Optical Diagnostics for Flow Processes written by P. Buchhave and published by Springer. This book was released on 2013-07-18 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Advanced Optical and 3D Reconstruction Diagnostics for Combustion and Fluids Research written by Qian Wang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Turbulent Reacting Flows at High Speed written by and published by . This book was released on 2001 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall goal of the research was to establish a strong foundation for understanding and predicting the interaction of fluid mechanical processes with chemical reactions in high speed flows. To accomplish this goal, expertise in chemical kinetics, experimental fluid mechanics and combustion, and computational fluid mechanics were brought together to make a systematic attack on turbulent reacting flows at high speed. In particular, the following tasks were established Task 1: High Speed Flow Experiments Including Mixing and Heat Release Task 2: Fundamental Combustion Experiments and Modeling Task 3: The Development and Application of Advanced Optical Diagnostics Task 4: Numerical Simulation Of Reacting Flows At High Speed The report summarizes the goals of the research and the progress made in each of these tasks.
Download or read book Reactive Flow Visualization Through High speed Optical Laser Diagnostics written by Constandinos Miltiadis Mitsingas and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Advanced Diagnostics for Reacting Flows written by and published by . This book was released on 1993 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is reported for the past year of an interdisciplinary program aimed at establishing advanced optical diagnostic techniques applicable to combustion gases and plasmas, with some emphasis on high speed flows. The primary parameters of interest are species concentrations (including electrons), temperature, mass density, pressure, velocity, and quantities derivable from these parameters such as mass flow rate (from the product of density and velocity). The techniques under study are based on laser spectroscopy, particularly laser absorption and laser-induced fluorescence, with the latter capable of providing both single-point and multi-point (2-D and 3-D) measurements. Laser sources include tunable cw lasers (ring dye and semiconductor diode lasers) and tunable pulsed lasers (excimer-pumped dye and narrow-linewidth excimer). The cw lasers are spectrally narrow, allowing study of a new class of techniques based on spectral lineshapes and shifts, while the pulsed lasers provide intense bursts of photons needed for techniques based on light-scattering phenomena.
Download or read book Coded Optical Imaging written by Jinyang Liang and published by Springer Nature. This book was released on with total page 697 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of SAE China Congress 2016 Selected Papers written by China Society of Automotive Engineers and published by Springer. This book was released on 2017-03-07 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume gathers outstanding papers submitted to the 2016 SAE-China Congress, the majority of which are from China, the biggest car maker as well as most dynamic car market in the world. The book includes insights into the current challenges that the whole industry is currently facing, and it offers possible solutions to problems such as emission controls, environmental pollution, the energy shortage, traffic congestion and sustainable development. It also presents the latest technical achievements in the automotive industry. Many of the approaches it presents can help technicians to solve the practical problems that most affect their daily work.
Download or read book F S Index United States Annual written by and published by . This book was released on 1999 with total page 1980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Diagnostics of Gas dynamic Flows Using Advanced Laser Measurement Techniques written by Kenneth P. Gross and published by . This book was released on 1985 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 30th AIAA Fluid Dynamics Conference written by and published by . This book was released on 1999 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 38th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit 02 3850 02 3899 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 Optics and Spectroscopy for Fluid Characterization written by Johannes Kiefer and published by MDPI. This book was released on 2018-08-20 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue " Optics and Spectroscopy for Fluid Characterization" that was published in Applied Sciences
