This thesis is primarily about the mapping and analyze of the phenomenon of an impinging jet by experimental measurements and numerical simulations by CFD. The mapping shows the characteristics of velocity in and around the impinging jet with different conditions. Additional studies were made by analyzing the pressure along the vertical jet axis, but also weight measurements were part of the investigation. The measurements covered the range from 10 m/s, 20 m/s and 30 m/s, which corresponds to a Reynolds number of 17 000, 34 000 and 50 000. The impinging jet is therefore considered to be highly turbulent. The main difference from previous studies is the use of the ultrasonic anemometer to measure the velocities. These create the ability of measuring the velocities on three coordinates. The jet’s contour was crucial to determine the penetration of ambient air flowing into the jet with an angle of around 88° and the entrainment of the ambient air multiple the jet volume flow. In comparison with CFD, the number of cells in the mesh design and the type of model plays a substantial role. The model k-ε Realized came closest to the experimentally measurements, while the SST k-ω and RNG k-ε EWF had far more entrainment of the ambient air into the impinging jet. / Detta examensarbete handlar om att kartlägga och analysera fenomenet av en ”impinging jet” genom experimentella mätningar samt numeriska simuleringar som CFD. Undersökningen visar karakteristiken av hastigheten i och kring strålen med olika förutsättningar. Kompletterande undersökningar gjordes för trycket i luftstrålens centrum längs den vertikala axeln, men även viktmätningar var del av undersökningen. Mätningarna omfattade hastigheter från 10 m/s, 20 m/s och 30 m/s som motsvarar ett Reynoldstal med 17 000, 34 000 och 50 000. Luftstrålen betraktas därför som turbulent. Det som skiljer sig från tidigare experiment är att hastigheten mättes med en ultrasonic anemometer som egentligen används inom metrologin för att mäta vindhastigheter. Därmed skapades en tredimensionell bild av hastigheten i och kring luftstrålen. Mätområdet sträckte sig från strålens utgångspunkt ner till strax ovanför plattan. Luftstrålens fastställda kontur var avgörande för att bestämma den inträngande omgivningsluften som strömmar in i strålen med en genomsnittlig vinkel av 88°. Denna inströmmande omgivningsluft flerfaldigade strålens volym. I jämförelse med CFD simuleringen visades att antal celler i meshen är avgörande för att skapa liknande och reala förutsättningar. Vid undersökningen av den inträngande omgivningsluften visades även att själva modellen spelar en avgörande roll. Det var modellen k-ε Realized som kom närmast mätningarna. Däremot uppvisade SST k-ω och RNG k-ε EWF modellerna mycket mer inträngande omgivningsluft i jämförelse med mätningarnas resultat.

Seafloor hydrothermal systems play a key role in Earth fs energy and geochemical budgets. They also support the existence and development of complex chemosynthetic biological ecosystems that use the mineral-laden fluids as a source of energy and nutrients. This dissertation focuses on two inter-related topics: (1) heat output and geochemical fluxes at mid-ocean ridges, and (2) structural deformation of oceanic lithosphere related to subsurface serpentinization in submarine settings. The determination of heat output is important for several reasons. It provides important constraints on the physics of seafloor hydrothermal processes, on the nature of the heat sources at mid-ocean ridges, and on nutrient transport to biological ecosystems. Despite its importance, measurements of hydrothermal heat outputs are still scarce and cover less than 5% of active hydrothermal vent sites. In this work, we report development of two new devices designed to measure fluid flow velocities from the submersible at temperatures of up to 450 C and depths 5,000 m. By using these instruments on 24 Alvin dives, new measurements of hydrothermal heat output have been conducted at the Juan de Fuca Ridge, including first measurements from the High Rise and Mothra hydrothermal fields. The collected data suggest that the high-temperature heat output at the Main Endeavour Field (MEF) may be declining since the 1999 eruption. The flow measurement results, coupled with in-situ geochemical measurements, yielded the first estimates of geochemical fluxes of volatile compounds at MEF and Mothra. Our findings indicate that geochemical flux from diffuse flows may constitute approximately half of the net geochemical flux from Juan de Fuca Ridge. It has recently been recognized that serpentinization of mantle peridotites, due to its exothermic nature, may be a mechanism contributing to the heat output at mid-ocean ridges. The tectonic response of the crust to serpentinization of extensively distributed peridotites at mid-ocean ridges and subduction zones could provide a means of characterizing serpentinized regions in the oceanic lithosphere. These regions are often associated with surface topographic anomalies that may result from the volume expansion caused by the serpentinization reactions. Although there is a clear correlation between tectonics and serpentinization, the link is complex and still not understood. In this dissertation, we calculated the transformation strain and surface uplift associated with subsurface serpentinization of variously shaped ultramafic inclusions. Application of the results to explain the anomalous topographic salient at the TAG hydrothermal field (Mid-Atlantic Ridge) suggests that this feature may result from a serpentinized body beneath the footwall of a detachment fault. Because the depth of the potential serpentinized region appears to be more than 1.5 times the size of the inclusion, the uplift profile is relatively insensitive to the exact location or shape of the serpentinized domain. The rate of exothermic heat release needed to produce the serpentinized volume may contribute to the ongoing diffuse flow. Application of the results to an uplift feature associated with the Kyushu ]Palau subduction zone in the western Pacific, shows that approximately 3% transformational strain in an inclined serpentinized region of the mantle wedge near the subducted Kyushu ]Palau Ridge may result in the observed uplift on the Miyazaki Plain. Using the uplift data may help to constrain the level of the subsurface serpentinization.

No description available.

This work is concerned with the characterization of slowly moving fluids and was carried out on the flow of water through a narrow sedimentation tank. Dispersion in the type of flow structure involved is caused mainly by the presence of large eddies and, due to the fact that shear stresses are small, these eddies persist for a considerable period of time. Two flow models are presented : The first model assumes the X- Y- velocity component pair to form a discrete state Markov process in time and dispersion equations for the mean concentration at a point, the variance as well as concentration cross correlations are generated. In the second model the velocity fluctuation components are assumed to be independent, time-stationary Markov processes with normal probability density functions. The stochastic differential equation describing dispersion of tracer is formulated with and without the effect of molecular diffusion and solutions to both cases are presented. Comparison of the model with experimental data obtained from tracer and anemometer measurements show that the model is capable of describing mean dispersion in a relatively small region of the tank and that the tracer experiments were insensitive to molecular diffusion. / Thesis (Ph.D.)-University of Natal, Durban, 1970.

The objective of this thesis was to develop a novel understanding of the mechanics of two phase gas-liquid flows and sprays injected through industrial effervescent nozzles. This was done using detailed experimental investigations and scaling for two-phase flows and sprays. This study helps to quantify near-field liquid and gas phase statistics that are challenging and impossible to measure in the reactors due to inaccessibility restrictions. The development of nozzles is generally performed on air-water systems. My plan was to begin with the study of small-scale sprays (air and water) to compare to full scale industrial conditions at pilot operation (air-water) or at commercial operation (steam-bitumen), to determine size scaling relationships. The relationship between the lab scale air-water experiments and real industrial scale steam-bitumen has never been fully examined. Knowledge from this thesis will make the development of future nozzles with much less dependent on trial and error. This thesis was an attempt to establish fundamental scaling relationships for the prediction of two-phase spray behavior that can be applied directly to full scale industrial size nozzles that would be of very significant value to industries and to the scientific community in general. Understanding the performance of two phase nozzles through established scaling laws will aid in optimizing the two phase nozzle flow conditions and will serve as a major tool in nozzle design and development for future generation nozzles for many industrial applications.

To continue the development of the Boundary Layer Data System (BLDS), a constant voltage hot-wire anemometer (CVA) is implemented into the BLDS for flight-testing. The hot-wire anemometer was chosen as an alternative to the traditional pressure probe because of the ability to measure both average velocity and fluctuating velocity within the boundary layer. Previous work done on the benchtop has led to the design of miniaturization, flight-capable hardware for the BLDS. The next step in the development of the BLDS – CVA calls for quantifying the accuracy of the boundary layer measurements measured by the CVA system. To do this, numerous turbulent boundary layer velocity and fluctuating velocity profiles were taken on a flat-plate at various speeds within the Cal Poly 2x2 wind tunnel with both the traditional pressure probe and the CVA. These test resulted showed agreement between the hot-wire and pressure probe data. Once this was completed the new CVA hardware was tested along with the new software that was written for the BLDS – CVA. In addition, due to the limited memory space onboard the BLDS – CVA, an approximation had to be developed to convert the average voltage data from the BLDS – CVA to the average velocity data due to the non-linear calibration function. The approximation developed was able to match the exact values from a traditional calibration. Lastly, due to the inability to perform a laboratory calibration of the hot-wire at altitude, where the conditions differ significantly from the ground conditions, a new procedure for hot-wire calibration was developed. The method developed was validated through wind tunnel testing and a computer thermal/electric model. With the completion of this work, the BLDS – CVA is ready for flight-testing.

The work deals with development and assembly of ultrasonic airflow measurement module for measurement of air flowing around photovoltaic panel. This system allows quantification of photovoltaic panel air cooling. The work contains development of sine wave generator, bridge amplifier and receiver with passive band pass filter, amplifier and comparator. It also deals with digital part realization. This digital part is formed by Renesas 78K0R microcontroller on demo board. The last part of this work contains testing of the whole system in aerodynamic tunnel and on photovoltaic panel installation.

This master’s thesis deals with the construction and realization of an ultrasound anemo- meter. Individual types of anemometers are compared in this thesis, including mechanical, thermo anemometer and ultrasound anemometer. Different construction renderings and measurement principles of ultrasonic anemometers are analyzed. In addition, an experi- mental method of measuring the speed of sound by phase shift between two transmitting frequency is described in the document. This thesis includes the design of an control unit and the realization of a simple prototype of an ultrasonic anemometer. Experimental confirmation of the characteristics of the ultrasound anemometer is the last part of the document.

Non-intrusive acoustic instruments that measure fluid velocity and temperature have been restricted to low subsonic Mach number applications due to increased complexities associated with acoustic refraction, low signal-to-noise ratios, and a limited range of practical applications. In the current work, the use of acoustics for non-intrusive flow monitoring in compressible flows is explored and a novel sonic anemometry and thermometry (SAT) technique is developed. Using multiple arrangements of SAT equipment, a compressible acoustic tomography technique was also developed to resolve flow non-uniformities. Three validation experiments were used to investigate the novel SAT technique performance, and a fourth validation experiment was used to explore compressible flow tomography capabilities. In the first experiment, an unheated jet was used to verify that the acoustic technique could measure fluid velocities in high subsonic Mach number flows. The application demonstrated velocity root mean square (RMS) errors of 9 m/s in unheated jet flows up to Mach 0.83. Next, a heated jet facility was used to assess the impact of fluid temperature on measurement accuracy. Using jet Mach numbers up to 0.7 and total temperatures up to 700 K, RMS velocity and static temperature errors up to 8.5 m/s (2.4% of maximum jet velocity) and 23.3 K (3.3% of total temperature) were observed. Finally, the acoustic technique was implemented at the exhaust of a JT15D-1A turbofan engine to investigate technique sensitivity to bypass engine conditions. A mass flow rate and thrust estimation approach was developed and RMS errors of 1.1 kg/s and 200 N were observed in conditions up to an exhaust Mach number of 0.48. Since modern acoustic tomography techniques require an incompressible flow assumption for velocity detection, advancements were made to extend acoustic tomography methods to compressible flow scenarios for the final experiment. The approach was tested in the heated jet operating at Mach 0.48 and 0.72 (total temperature of 675 K, approximately 2.25 times the ambient) and numerical simulations were used to identify technique sensitivity to input variables and system design. This research marks the first time an acoustic method has been used to estimate compressible flow velocities and temperatures. / Ph. D.

För att ta reda på användbarheten av en specialkonstruerad lättviktsanemometer när det gälleratt beräkna turbulenta flöden, har mätdata från instrumentet använts i den så kallade inertialdissipationsmetoden. Resultatet har jämförts med direkta flödesberäkningar från enljudanemometer enligt turbulenta utbytesmetoden, vilka antas vara korrekta. Resultatanalyshar utförts från mätningar på höjderna 8, 16 och 20 m. Lättviktssanemometern (inertialdissipationsmetoden) visade sig stämma bra överens med ljudanemometern (turbulentautbytesmetoden) under nära neutrala förhållanden och vid höga vindhastigheter. Resultatenvisar ett inflytande av havsvågor och den bör därför användas vid uppbyggande sjö för attundvika detta. I rapporten presenteras en rekommendation med nödvändiga korrektioner föranvändning av lättviktsanemometern till turbulenta flödesberäkningar enligt inertialdissipationsmetoden. / In order to evaluate a combined cup anemometer/wind vane profile instrument, measurementsfrom the instrument has been used in the so called inertial-dissipation method to derive itsability to measure turbulent fluxes. The result was compared to data from a sonic anemometercalculated with eddy-correlation method, which is assumed to be correct. Analysis of theresult was made from measurements at levels 8, 16 and 20 m. The profile instrument (inertialdissipationmethod) agreed well with the sonic anemometer (eddy-correlation method) duringnear neutral conditions and at high wind speed. The profile instrument also proved to be mostaccurate at conditions of growing sea, otherwise the result was affected by waves. In thereport there is also a recommendation for specific corrections when the profile instrument isused for calculating turbulent fluxes according to the inertial-dissipation method.