The development of high-speed PIV techniques and their application to jet noise measurement

This thesis describes the design, development and deployment of a high-speed jet flow measurement system. The apparatus was created in response to the need to collect a large quantity of statistically-converged aerodynamic data from a series of commercial turbofan engine models. This acquisition was performed in conjunction with acoustic measurements as part of the ED CoJeN project to investigate jet noise production, and associated noise reduction techniques. Particle Image Velocimetry is a well established flow measurement technique, but its application outside of the laboratory can be limited by a relatively low sample rate and' the need to operate in a hostile environment. This thesis presents a multiple camera technique - used as the basis for the j et measurement system - that is capable of acquiring both time-series PIV data at MHz rates, and continuous, statistically independent measurements at up to 14 Hz. The resultant PIV measurement rig was therefore capable of acquiring time-averaged velocity and turbulence data from the whole of a 110 scale coaxial engine exhaust plume (down to 4m or 20D) in no more than 1 hour. The -500aC Mach:5 0.9 jets were also scanned volumetrically in order to check the spatial alignment of the nozzle and flow streams,.and all PIV measurements were synchronised to simultaneous LDA acquisition, thus enabling the data to be validated. Finally, the cameras were used to acquire novel6-frame time-series data at:5 330 kHz, which was used to calculate time-space correlations within the exhaust. By providing a highly automated and completely remote-controlled system, the exhaust measurements could be repeated over 3 operating conditions and 2 nozzle geometries, thereby providing a comprehensive description of the flow field. The data, having been systematically post-processed, has been shown to agree well with concurrent measurements, and it will now be used to validate CFD models of coaxial jet flow. By improving the quality of computational flow prediction in this way, the time taken to design and test quieter jet engines will be significantly reduced.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The spatial and temporal characterisation of functional interactions between the key membrane stress proteins at the single molecule level in live Escherichia coli cells

All the cell types must maintain the integrity of their membranes which is important for cell viability. The membrane structure and function is maintained by many different response mechanisms. One such unique bacterial membrane stress response is the Phage shock protein response (Psp). It is composed of a transcriptional activator, negative regulator, signal sensors and transducers and stress effectors. Using milli second time-scale single-molecule fluorescence microscopy in live E. coli cells, the localisations, two dimensional diffusion dynamics and stoichiometry of functional Psp proteins were determined under non-stress and membrane stress conditions. The two major proteins studied in this research are a bacterial enhancer binding protein phage shock protein F (PspF) and the negative regulator and major effector phage shock protein A (PspA). For the imaging studies stable and functional chromosomal fusions of PspF and PspA to Venus fluorescent protein were used replacing the native proteins. It was established that a stable repressive PspF-PspA complex is located in the nucleoid and PspF displays DNA associated diffusion dynamics similar to other DNA-binding transcription factors such as LacI. PspF as a hexamer activated a single psp promoter at a time. The effector V-PspA assembled as higher order oligomers localised at the lateral membrane and showed very slow dynamics. In addition in vivo and in vitro structural studies of PspA showed that N-terminal amphipathic helix governed the balance between the dual functions of PspA. In a proposed model of the cellular landscape of the Psp response, the PspF-PspA inhibitory complex localised at the nucleoid transiently communicated with the polar regions of cells occupied by PspBC under non-stress conditions. With the stress conditions PspA retained at the polar membrane along with PspBC, while PspF associated with the active transcription complex to initiate the expression of psp genes. With the increase in the amounts of PspA, it organised itself into higher order effector moving along the MreB directed helical path contacting with the membrane via RodZ and in this way facilitated the organisation of membrane repair pathways at the damaged sites.Open Acces

Microfluidics and Nanofluidics Handbook

The Microfluidics and Nanofluidics Handbook: Two-Volume Set comprehensively captures the cross-disciplinary breadth of the fields of micro- and nanofluidics, which encompass the biological sciences, chemistry, physics and engineering applications. To fill the knowledge gap between engineering and the basic sciences, the editors pulled together key individuals, well known in their respective areas, to author chapters that help graduate students, scientists, and practicing engineers understand the overall area of microfluidics and nanofluidics. Topics covered include Finite Volume Method for Numerical Simulation Lattice Boltzmann Method and Its Applications in Microfluidics Microparticle and Nanoparticle Manipulation Methane Solubility Enhancement in Water Confined to Nanoscale Pores Volume Two: Fabrication, Implementation, and Applications focuses on topics related to experimental and numerical methods. It also covers fabrication and applications in a variety of areas, from aerospace to biological systems. Reflecting the inherent nature of microfluidics and nanofluidics, the book includes as much interdisciplinary knowledge as possible. It provides the fundamental science background for newcomers and advanced techniques and concepts for experienced researchers and professionals

Particle image velocimetry investigation of the wake fields of a long flexible riser

Vortex-Induced Vibration of marine risers has been receiving increasing interest from both industry and academics as offshore oil and gas exploration moves into deeper water regions. A regular vortex pattern is formed in the wake of cylindrical risers that interacts with the cylinder motion and is the main source that causes elastically mounted cylinders to vibrate. Wake field studies of Vortex-Induced Vibration (VIV) for a long flexible cylinder can help to better understand the physical mechanisms of the interaction between the body response and the wake vortex. The presented work consists of two major parts: some preliminary tests for the Digital Particle Image Velocimetry (DPIV) system of the Memorial University of Newfoundland (MUN) and the Vortex-Induced Vibration (VIV) wake field research using DPIV. These preliminary tests were conducted in small water tanks and the MUN towing tank. Some essential parameters and techniques using PIV were also investigated through these preliminary tests. The VIV wake field measurement experiments were performed in the ice tank, Institute for Ocean Technology (IOT). Vibration responses in both in-line and cross-flow directions of a long flexible cylinder, with a diameter of 47mm and length to diameter ratio of 181, in a free stream, were investigated at moderate Reynolds number in the range of 9400-47000. The DPIV system was employed to measure the wake velocity field and vorticity field behind the cylinder, simultaneously with acceleration measurements of the cylinder. The experimental results show VIV responses in both in-line and cross-flow directions at the span location z/L=0.43, and with a mix of vibration frequencies and amplitudes. With the increase of the flow speeds, vibration frequencies became higher in both in-line and cross-flow directions. The vibration frequencies of the cylinder were in a range of 0.64 Hz to 10.38 Hz over the range of Reynolds numbers. The amplitude did not obviously increase with an increase of Reynolds number. The amplitude to diameter ratio in the in-line and cross-flow directions covered a range of 0.10 - 0.41 and 0.24-0.95, respectively. The flow field measurement results reveal that for a certain value of the vibration frequency, f, the Reynolds number, Re, and the amplitude to diameter ratio, AID, three vortex modes '2S', '2P' and 'P+S' are observed in the near wake of the cylinder. At the lower Reynolds number, Re=9400, and with lower response frequencies from 0.61 Hz to 1.28 Hz, only '2S' vortex modes were observed in the experiments, and the '2S' vortex modes presented were stable. With an increase of the Reynolds number, at Re= 141 00 and with frequencies from 0.95 Hz to 2.74 Hz, two vortex modes, '2P' and 'P+S', were observed in the near wake at different times. The '2P' mode was dominant at this Reynolds number. Vortex modes '2S' and '2P' were observed at different times when the Reynolds number further increased, to Re=18800 and 23500 and with frequencies from 1.34 Hz to 4. 79 Hz. The vortex pattern '2S' played a main role in the wake at the two speeds. At higher Reynolds number, Re>23500, and with frequencies from 1.86 Hz to 10.38 Hz, '2S' and '2P' vortex modes were also observed at different times and the vortex patterns presented were unstable due to velocity fluctuation and quick diffusion of vortices in the wake. The percentage of the vortex pattern '2P' increases at higher speeds. The results also showed that the vortex modes '2S' and '2P' were repeatable with the same vibration responses of displacements and accelerations

NASA Tech Briefs, January 2007

Topics covered include: Flexible Skins Containing Integrated Sensors and Circuitry; Artificial Hair Cells for Sensing Flows; Video Guidance Sensor and Time-of-Flight Rangefinder; Optical Beam-Shear Sensors; Multiple-Agent Air/Ground Autonomous Exploration Systems; A 640 512-Pixel Portable Long-Wavelength Infrared Camera; An Array of Optical Receivers for Deep-Space Communications; Microstrip Antenna Arrays on Multilayer LCP Substrates; Applications for Subvocal Speech; Multiloop Rapid-Rise/Rapid Fall High-Voltage Power Supply; The PICWidget; Fusing Symbolic and Numerical Diagnostic Computations; Probabilistic Reasoning for Robustness in Automated Planning; Short-Term Forecasting of Radiation Belt and Ring Current; JMS Proxy and C/C++ Client SDK; XML Flight/Ground Data Dictionary Management; Cross-Compiler for Modeling Space-Flight Systems; Composite Elastic Skins for Shape-Changing Structures; Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells; Aligning Optical Fibers by Means of Actuated MEMS Wedges; Manufacturing Large Membrane Mirrors at Low Cost; Double-Vacuum-Bag Process for Making Resin- Matrix Composites; Surface Bacterial-Spore Assay Using Tb3+/DPA Luminescence; Simplified Microarray Technique for Identifying mRNA in Rare Samples; High-Resolution, Wide-Field-of-View Scanning Telescope; Multispectral Imager With Improved Filter Wheel and Optics; Integral Radiator and Storage Tank; Compensation for Phase Anisotropy of a Metal Reflector; Optical Characterization of Molecular Contaminant Films; Integrated Hardware and Software for No-Loss Computing; Decision-Tree Formulation With Order-1 Lateral Execution; GIS Methodology for Planning Planetary-Rover Operations; Optimal Calibration of the Spitzer Space Telescope; Automated Detection of Events of Scientific Interest; Representation-Independent Iteration of Sparse Data Arrays; Mission Operations of the Mars Exploration Rovers; and More About Software for No-Loss Computing

Behavioral responses of invertebrate larvae to water column cues

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2016Many benthic marine invertebrates have two-phase life histories, relying on planktonic larval stages for dispersal and exchange of individuals between adult populations. Historically, larvae were considered passive drifters in prevailing ocean currents. More recently, however, the paradigm has shifted toward active larval behavior mediating transport in the water column. Larvae in the plankton encounter a variety of physical, chemical, and biological cues, and their behavioral responses to these cues may directly impact transport, survival, settlement, and successful recruitment. In this thesis, I investigated the effects of turbulence, light, and conspecific adult exudates on larval swimming behavior. I focused on two invertebrate species of distinct morphologies: the purple urchin Arbacia punctulata, which was studied in pre-settlement planktonic stages, and the Eastern oyster Crassostrea virginica, which was studied in the competent-to-settle larval stage. From this work, I developed a conceptual framework within which larval behavior is understood as being driven simultaneously by external environmental cues and by larval age. As no a priori theory for larval behavior is derivable from first principles, it is only through experimental work that we are able to access behaviors and tie them back to specific environmental triggers. In this work, I studied the behavioral responses of larvae at the individual level, but those dynamics are likely playing out at larger scales in the ocean, impacting population connectivity, community structure, and resilience. In this way, my work represents progress in understanding how the ocean environment and larval behavior couple to influence marine ecological processes.This work was funded by the National Science Foundation under grant OCE-0850419 (to LS Mullineaux and KR Helfrich), by the National Oceanic and Atmospheric Administration Sea Grant NA14OAR4170074 (to LS Mullineaux, KR Helfrich, and JD Wheeler), grants from WHOI Coastal Ocean Institute, discretionary WHOI funds, a WHOI Ocean Life Fellowship (LS Mullineaux), and a Grove City College Swezey Fund Grant (EJ Anderson)

Experimental analysis of crankcase oil aerosol generation and control

Crankcase ventilation contributes significantly to diesel engine particulate emissions. Future regulations will not only limit the mass of particulate matter, but also the number of particles. Controlling the source of crankcase emissions is critical to meeting the perennial legislation. Deficiency in the understanding of crankcase emissions generation and the contribution of lubricating oil has been addressed in detail by the experimental study presented in this thesis. A plethora of high speed laser optical diagnostics techniques have been employed to deduce the main mechanisms of crankcase oil aerosol generation. Novel images have captured oil atomisation and passive oil distribution around the crankcase of an optically accessed, motored, four cylinder, off highway, heavy duty, diesel engine. Rayleigh type ligament breakup of oil films present on the surface of dynamic components, most notably the crankshaft, camshaft and valve rockers generated oil drops below 10 micrometers. Data illustrated not only crankcase oil aerosol generation at source, but it has provided valuable information on methods to control oil aerosol generation and improve oil circuit efficiency. The feasibility of utilising computational fluid dynamics to predict crankcase oil aerosol generation has been successfully assessed using the experimental data. Particle sampling has characterised the crankcase emissions from both a fired and motored diesel engine crankcase. The evolution of submicron crankcase particles down to 5 nm has been recorded from both engines, including the isolated contribution of engine oil, at a wide range of engine test points. Results have provided constructive insight into the generation and control of this complex emission. The main mechanism of crankcase oil aerosol generation was found to be crankshaft oil atomisation. This atomisation process has been analysed in detail, involving high speed imaging of primary and satellite drop generation and high speed digital particle image velocity of the crankshaft air flow. A promising mechanism of regulating and controlling crankcase oil aerosol emissions at source has been studied experimentally

DEVELOPMENT OF MEASUREMENT AND VISUALIZATION TECHNIQUES FOR CHARACTERIZATION OF MIXING AND COMBUSTION PROCESSES WITH SURROGATE FUELS

[EN] The development and optimization of new combustion modes is nowadays an important research field, to reduce the pollutant emissions of the reciprocating internal combustion engines. Their development requires the use of a wide variety of experimental and theoretical tools, which make it possible to know and understand their fundamentals. In this context the main objective of this Thesis is framed: the development and optimization of measuring and visualization techniques, to reach the level of accuracy and detail required for current and future studies of that kind. The work has been based on the characterization of the diesel diffusion combustion to be able to focus the study on the methodological part, thanks to the extensive knowledge available on this combustion mode. The work has been divided in two main blocks. The first one is focused on the characterization of evaporation and air-fuel mixture formation processes. For this purpose, a new technique has been developed and applied, based on the light absorption by the fuel molecules (UV-VIS LAS), which allows measuring the vapour fuel local concentration within a diesel spray. It has been optimized to be applied under operating conditions similar to those found in a compression ignition engine with fuels whose optical properties are not optimal, but which are interesting for research due to its simplicity. Moreover, a new methodology has been developed for measuring the absorption coefficient of the fuels, under similar operating conditions (i.e. pressure and temperature) than those found within the combustion chamber of a compression ignition engine. Results have been analysed in detail, to be able to define the limitations and reliability of the methodology proposed. The second block corresponds to the characterization of the combustion process and the soot formation. For this purpose, a complex optical set-up has been developed which made it possible to simultaneously apply the three most used techniques that can be found in literature for soot measuring within a diesel flame: Laser Extinction Method, 2-Colour Pyrometry and Laser-Induced Incandescence. Results obtained by means of the three techniques have been compared in detail, not only to identify the main advantages and drawbacks of each technique, but also their reliability under different operating conditions.[ES] El desarrollo y optimización de nuevos modos de combustión constituye actualmente un campo importante de investigación, para reducir la emisión de contaminantes en motores de combustión interna alternativos. Su desarrollo requiere del uso de gran variedad de herramientas experimentales y teóricas, que permitan conocer y comprender sus fundamentos. En este contexto se enmarca el objetivo principal de esta Tesis: la mejora y el desarrollo de técnicas de visualización y medida, para alcanzar el nivel de detalle y la precisión requeridos para estudios actuales y futuros de esta índole. El trabajo se ha basado en la caracterización de la combustión diésel por difusión para poder centrar el estudio en la parte metodológica, gracias al amplio conocimiento disponible sobre este modo de combustión. El trabajo se ha dividido en dos apartados principales. El primero de ellos se centra en la caracterización de los procesos de evaporación y formación de la mezcla aire-combustible. Para ello, se he desarrollado y puesto en práctica una técnica basada en la absorción de luz por parte de las moléculas de combustible (UV-VIS LAS), que permite medir la concentración local de combustible evaporado en el seno de un chorro diésel. Esta ha sido optimizada para ser aplicada en condiciones de operación semejantes a las de un motor de encendido por compresión con combustibles cuyas propiedades ópticas no son óptimas, pero que son de gran interés para investigación dada su simplicidad. Además, se ha desarrollado una metodología para la medida del coeficiente de absorción de los combustibles, bajo las mismas condiciones de operación (presión y temperatura) que las que se dan en la cámara de combustión de un motor de encendido por compresión. Los resultados obtenidos se han analizado con detalle, para poder definir los límites y la fiabilidad de la metodología propuesta. El segundo apartado corresponde a la caracterización del proceso de combustión y la formación de hollín. Para ello, se ha desarrollado un montaje óptico complejo que ha permitido aplicar de forma simultánea las tres técnicas más utilizadas en la literatura para la medida del hollín en una llama diésel: Método de Extinción Láser, Pirometría 2-Colores e Incandescencia Inducida por Láser. Los resultados obtenidos mediante las tres técnicas han sido comparados detalladamente, no sólo para identificar las principales ventajas e inconvenientes de cada técnica, sino también la fiabilidad de las mismas para distintas condiciones de operación.[CA] El desenvolupament y optimització de nous modes de combustió constitueixen actualment un camp important d'investigació, para reduir la emissió de contaminants en motors de combustió internat alternatius. El seu desenvolupament requereix del us de gran varietat de ferramentes experimentals i teòriques, que permeten conèixer i comprendre els seus fonaments. En este context s'emmarca l'objectiu principal d'esta tesi: la millora i el desenvolupament de tècniques de visualització i mesura, per a conseguir el nivell de detall i la precisió requerits per a estudis actuals i futurs d'esta índole. El treball s'ha basat en la caracterització de la combustió dièsel per difusió per a poder centrar l'estudi en la part metodològica, gràcies a l'ampli coneixement disponible sobre este mode de combustió. El treball s'ha dividit en dos apartats principals. El primer d'ells se centra en la caracterització dels processos d'evaporació i formació de la mescla aire-combustible. Per això, s'ha desenvolupat i posat en pràctica una tècnica basada en la absorció de llum per part de les molècules de combustible (UV-VIS LAS), que permet mesurar la concentració local de combustible evaporat en el si d'un esprai dièsel. Esta ha sigut optimitzada per a ser aplicada en condicions d'operació semblants a les d'un motor d'encesa per compressió i combustibles amb propietats òptiques que no son les òptimes, però els quals són de gran interés en investigació donada la seua simplicitat. A més, s'ha desenvolupat una metodologia per a la mesura del coeficient d'absorció dels combustibles, a les mateixes condicions d'operació (pressió i temperatura) que les que es donen en la cambra de combustió d'un motor d'encesa per compressió. Els resultats obtinguts s'han analitzat amb detall, per a poder definir els límits i la fiabilitat de la metodologia proposada. El segon apartat correspon a la caracterització del procés de combustió i la formació de sutja. Per a això, s'ha desenvolupat un muntatge òptic complex que permés aplicar de forma simultània les tres tècniques més utilitzades en la literatura per a la mesura de la sutja en una flama dièsel: Mètode d'Extinció Làser, Pirometria 2-Colors i Incandescència Induïda per Làser. Els resultats obtinguts per mitjà de les tres tècniques han sigut comparats detalladament, no sols per a identificar els principals avantatges i inconvenients de cada tècnica, sinó també la fiabilitat d'aquestes per a distintes condicions d'operació.Micó Reche, C. (2015). DEVELOPMENT OF MEASUREMENT AND VISUALIZATION TECHNIQUES FOR CHARACTERIZATION OF MIXING AND COMBUSTION PROCESSES WITH SURROGATE FUELS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58991TESI