Author: Mark Christian JohnsonPublisher:
ISBN:
Category :
Languages : en
Pages : 310
Book Description
Development of a 3-D Laser Doppler Anemometry System
Author: Mark Christian JohnsonPublisher:
ISBN:
Category :
Languages : en
Pages : 310
Book Description
Investigation of Laser Doppler Anemometry in Developing a Velocity-based Measurement Technique
Author: Ki Won JungPublisher:
ISBN:
Category :
Languages : en
Pages : 198
Book Description
Acoustic properties, such as the characteristic impedance and the complex propagation constant, of porous materials have been traditionally characterized based on pressure-based measurement techniques using microphones. Although the microphone techniques have evolved since their introduction, the most general form of the microphone technique employs two microphones in characterizing the acoustic field for one continuous medium. The shortcomings of determining the acoustic field based on only two microphones can be overcome by using numerous microphones. However, the use of a number of microphones requires a careful and intricate calibration procedure. This dissertation uses laser Doppler anemometry (LDA) to establish a new measurement technique which can resolve issues that microphone techniques have: First, it is based on a single sensor, thus the calibration is unnecessary when only overall ratio of the acoustic field is required for the characterization of a system. This includes the measurements of the characteristic impedance and the complex propagation constant of a system. Second, it can handle multiple positional measurements without calibrating the signal at each position. Third, it can measure three dimensional components of velocity even in a system with a complex geometry. Fourth, it has a flexible adaptability which is not restricted to a certain type of apparatus only if the apparatus is transparent. LDA is known to possess several disadvantages, such as the requirement of a transparent apparatus, high cost, and necessity of seeding particles. The technique based on LDA combined with a curvefitting algorithm is validated through measurements on three systems. First, the complex propagation constant of the air is measured in a rigidly terminated cylindrical pipe which has very low dissipation. Second, the radiation impedance of an open-ended pipe is measured. These two parameters can be characterized by the ratio of acoustic field measured at multiple locations. Third, the power dissipated in a variable RLC load is measured. The three experiments validate the LDA technique proposed. The utility of the LDA method is then extended to the measurement of the complex propagation constant of the air inside a 100 ppi reticulated vitreous carbon (RVC) sample. Compared to measurements in the available studies, the measurement with the 100 ppi RVC sample supports the LDA technique in that it can achieve a low uncertainty in the determined quantity. This dissertation concludes with using the LDA technique for modal decomposition of the plane wave mode and the (1,1) mode that are driven simultaneously. This modal decomposition suggests that the LDA technique surpasses microphone-based techniques, because they are unable to determine the acoustic field based on an acoustic model with unconfined propagation constants for each modal component.
Development Testing and Application of a Three-dimensional Laser Doppler Velocimeter for the Measurement of Gas Flows
Author: C. E. FullerDesign Considerations for a 3-D Laser Doppler Velocimeter for Studying Gravity Waves in Shallow Water
Author: Robert J. HallermeierPublisher:
ISBN:
Category : Fluid dynamic measurements
Languages : en
Pages : 8
Book Description
Development of a Miniature Fibre Optic Laser Doppler Velocimeter for 3D Flow Measurements in Turbomachinery
Author: Stephen AntrobusAdvanced Non-intrusive Instrumentation for Propulsion Engines
Author: North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Propulsion and Energetics Panel. SymposiumPublisher: North Atlantic Treaty Organization Resear Rganization
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 554
Book Description
Laser Doppler and Phase Doppler Measurement Techniques
Author: H.-E. AlbrechtPublisher: Springer Science & Business Media
ISBN: 3662051656
Category : Science
Languages : en
Pages : 741
Book Description
Providing the first comprehensive treatment, this book covers all aspects of the laser Doppler and phase Doppler measurement techniques, including light scattering from small particles, fundamental optics, system design, signal and data processing, tracer particle generation, and applications in single and two-phase flows. The book is intended as both a reference book for more experienced users as well as an instructional book for students. It provides ample material as a basis for a lecture course on the subject and represents one of the most comprehensive treatments of the phase Doppler technique to date. The book will serve as a valuable reference book in any fluid mechanics laboratory where the laser Doppler or phase Doppler techniques are used. This work reflects the authors' long practical experience in the development of the techniques and equipment, as the many examples confirm.
Scientific and Technical Aerospace Reports
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 456
Book Description
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.
Author: 
Author: