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Williams, R. "Submerged flame combustion." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636655.
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The objective of this work is to better understand the operation of Submerged Flame Burners, commonly known as Submerged Combustion Burners. Two main aspects require consideration, namely: practical applications of the technology in industry; secondly, theoretical modelling of the flame behaviour within the Submerged Combustion Burner in order to ensure flame stability in the burner and hence heat transfer efficiency and reliable operation. The current status of the Submerged Combustion Technology has been reviewed, detailing the separation equipment items that, overall, make up an industrial Submerged Combustion package. The functionality of the different items has been considered in the context of the primary objective of the equipment, i.e. the establishment of a stable flame within the Submerged Burner. Cases detailing specific instances of the application of Submerged Combustion technology in industry are presented in order that practical aspects of the operation of such units can be better appreciated. The flame system within the Submerged Burner has been modelled using a commercially available Computational Fluid Dynamic Package. A simplified model was used in order to represent the processes occurring within the burner for the combustion of methane with air as the oxidant. The K- turbulence model was used for the prediction of turbulence behaviour within the system. The results of the Computational Fluid Dynamic modelling cover a range of operating parameter values that might be expected to be encountered in industrial applications of Submerged Combustion. The results of the theoretical analysis have been considered in terms of the significance to the design and operation of industrial Submerged Combustion units. The discussions of the practical application of the technology have also led to recommendations being made in respect of the design of the ancillary equipment associated with the Submerged Combustion Burners. The observations made and conclusions drawn in this work provide a better understanding of the processes involved with the production of a stable flame within a Submerged Combustion Burner. Recommendations have been made for future work building on the work reported here.
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Varley, Juliet. "Submerged jet oxygenation." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334290.
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Grinsted, T. W. "Earthmoving in submerged sands." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374759.
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Hamad, Mohamed Khaled M. A. "Submerged vanes turbulence : experimental analysis." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/377436.
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Experimental study was conducted to analyze the physical flow turbulence and sediment distribution with submerged vane. The objectives behind the investigation were verified and compare results with the Odgaard theory, also; achieved to measure vertical pressures acting on both sides of submerged vane, calculate lift and drag forces, lift and drag coefficients experimentally, that the theory of Odgaard was fails to predict satisfactorily.
Other motivation of the study was investigates experimentally the hydrodynamic characterization of submerged vanes as; velocities fields, circulation, vorticity, bed topography, pressures, drag and lift forces with its coefficients, study physical fluid turbulence of submerged vanes as; Reynolds normal and shear stresses, turbulent kinetic energy and rate of dissipation, turbulence intensities, Kolmogorov scales, kinetic energy spectrum, turbulent velocities fields, fluctuating velocities and finally Reynolds stresses histograms.
Tests were conducted with clear water was transported throughout the re-circulated rectangular channel with cross-section 7.5 m long, 2.52 m wide channel with a bed consisting of 50 cm thick layer of sand with a median diameter of 1.6-mm and a geometric standard deviation of 1.36. Velocities were measured with a 7 Acoustic Doppler Velocimeter ADV, which were calibrated and checked periodically, depths and water surface elevations were measured with a gauge that could be read with an error of less than 0.3 mm. The current meter, gauges were mounted on a movable instrument sliding carriage, which rode on rails a top of the channel walls, on a traversing mechanism, which enabled them to be positioned at any desired location in the channel. Positioning and data sampling were controlled from a computer program.
The water surface elevations were used to determine water surface slope S and Darcy-Weisbach friction factor f=8gRS/u_o^2, where uo = undisturbed (pre-vane) cross-sectional-averaged velocity. In all tests, uo=0.2867 m/s, and the discharge Q=116,62 l/s =0.11662 m^3/s.
The vanes were made of 14 mm-thick PVC sheet, they were rectangular in shape, with height H = 7 cm = 0.4337d, and length L = 25 cm = 3.571H. In all tests, the vanes were placed at an angle of attack of 20 degrees with the channel centerline. Water depth was 0.1614 m, pre-vane water surface slope, friction factor and geometric standard deviation, sg, were 1.6×10^(-3), 0.045 and 1.36 respectively.
The Vectrinos were been calibrated to work at 25Hz and for each position taken data for 4 minutes, a sample volume that is located approximately 4.3 mm of the device. For each position there are seven Vectrinos 10 cm distance from one to other taking data, so data recorded 7 points at the same time. Data recorded were taking on about 24.080 points on whole the sectional cross channel, with the aim to measure the velocities once the channel-bed has reached to the permanent regime or steady state (equilibrium), during the measurements of velocities, we has taken the bed topography (bathymetry) of the channel-bed by using ADV.
In the current dissertation, we installed 30 piezometers in each side of Vane. Once obtained the experimental pressures measured at the laboratory on both sides of vane, the pressure difference between vane sides (¿P), and the perpendicular resultant force (FR¿) acting on the vane, first calculated the resultant force between drag and lift components (FR), then we used this force to calculate drag force FD and lift force FL, also calculated Drag coefficient CD, and finally we calculated the Lift coefficient CL.
Results, includes submerged vanes turbulence statistics as; Probability distribution of the velocity field, Reynolds stresses, Turbulence intensity, Kinetic and Dissipation energy, and finally, Kolmogorov turbulence scales. Other results contain energy spectrum, turbulent velocities fields, fluctuating velocities and Reynolds stresses histograms.El estudio experimental se ha llevado a cabo para analizar el funcionamiento, la turbulencia del flujo y el transporte de sedimentos con paneles sumergidos. Los objetivos tras la investigación fueron verificados y comparados con los resultados de la teoría de Odgaard, también; se han medido las presiones verticales que actúan sobre ambos lados de los paneles sumergidos, se han calculado las fuerzas de drag y lift y, sus coeficientes experimentalmente, ya que la teoría de Odgaard no pudo predecirlas satisfactoriamente. Otra motivación del estudio, fue investigar experimentalmente la caracterización hidrodinámica de los paneles sumergidos como; distribución de velocidades, circulación, vorticidad, topografía del fondo, presiones, fuerzas de drag y lift y sus coeficientes, tensiones de Reynolds, energía cinética turbulenta y disipación turbulenta, intensidades de turbulencia, escalas de Kolmogorov, espectro de energía cinética, campos de velocidades turbulentas, velocidades fluctuantes y finalmente, histogramas de las tensiones de Reynolds. Se realizaron pruebas en aguas claras, a lo largo de un canal rectangular con una sección de 7.5 m de largo, 2.52 m de ancho y un espesor de 50 cm de arena de 1.6 mm de diámetro medio y una desviación geométrica de 1.36. Las velocidades fueron medidas con 7 Acoustic Doppler velocímeter ADV, las que fueron calibradas y revisadas periódicamente, las profundidades y las alturas de superficie de agua fueron medidas con un limnímetro que puede leerse con un error de menos de 0.3 mm. Los paneles fueron construidos con placas de PVC de 14 mm de espesor, de forma rectangular, con altura H = 7 cm = 0.4337d y longitud L = 25 cm = 3.571H. En todos los ensayos, los paneles se colocaron con un ángulo de ataque al flujo de 20 grados con la línea central del canal. El calado del agua es de 0.1614 m, la pendiente superficie, el factor de fricción y la desviación geométrica, fueron, 0.045 y 1.36 respectivamente. Los Vectrinos se han calibrado para trabajar a 25Hz y con un volumen de control de 4.3 mm, para cada posición se tomaron datos durante 4 minutos. Para cada posición hay siete Vectrinos con una distancia de 10 cm entre ellos, registrando por lo tanto 7 puntos al mismo tiempo. Los datos registrados fueron alrededor de 24,080 puntos en toda la sección del canal, con el objetivo de medir las velocidades una vez los sedimentos en el canal han alcanzado el régimen permanente o estacionario (equilibrio), durante las mediciones de las velocidades, se ha medido la topografía del fondo (batimetría) mediante el uso de los sensores ADV. La tesis actual, ha desarrollado un sistema para medir la presión vertical que actúa sobre ambas caras del panel, se instalaron 30 piezómetros de plástico en cada lado del panel. Una vez obtenida la presión experimental medida en el laboratorio a ambos lados del panel, se halla la diferencia de presión entre los dos lados, y la fuerza perpendicular resultante actuando sobre el panel, primero se calculó la fuerza resultante entre los dos componentes de drag y lift, para utilizarla después en el cálculo de la fuerza del drag FD y lift FL, así como el coeficiente de arrastre CD, y finalmente se calculó el coeficiente de lift CL. Los resultados de turbulencia incluyen; Distribución de probabilidad de la distribución de velocidades, tensiones de Reynolds, intensidad turbulenta, energía cinética y disipación. Finalmente, escalas de turbulencia de Kolmogorov. Otros resultados contienen el espectro de energía, campos de velocidades turbulentas, velocidades fluctuantes y los histogramas de las tensiones de Reynolds.
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Sharif, Ahmadian A. "Wave field around submerged breakwaters." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1414995/.
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Shoreline response to submerged breakwaters is particularly influenced by the wave field behind the structure driven by coastal processes. The 2D aspects of wave transmission behind submerged breakwaters have been extensively studied by researchers. However, available 2D engineering design tools are inefficient in breakwater design due to not being able to provide any information on the spatial distribution of the nearshore wave field around the breakwater. There are very few studies considering 3D effects in the literature and consequently no reliable guidance for engineers. This encouraged the author to investigate this subject experimentally and numeri¬cally, with the aim of contributing to this important research topic. A comprehensive set of 2D and 3D experiments has been conducted in three wave tanks with different scales. A method has been prepared for predicting the waves transmitted behind the breakwaters based on the data-driven algorithms called Artificial Neural Networks (ANN) and using some of the experimental data collected. Multi-layer perceptron (MLP) and Radial basis function (RBF) models were designed and trained by the Levenberg-Marquardt learning algorithm (LM) and a derivative- based algorithm of gradient descent (GD) respectively. To verify the numerical model, wave simulation was also carried out using DHI MIKE 21 BW (2DH Boussinesq Wave module) based on the numerical solution of the time domain formulations of Boussinesq type equations. The spatial variations of wave energy and wave pattern around the breakwater were generally found to depend on incident wave climate and whether or not wave breaking occurred over the breakwater as well as degree of breaking, with different wave patterns observed for different wave conditions. In cases with waves breaking over the breakwater the lower wave heights were observed behind the breakwater crown on the shorewardside; for nonbreaking wave conditions passing over the submerged breakwater lower wave heights were observed in the gap between the end of the breakwater and the flume wall. Investigations illustrated that the dimensionless Cartesian coordinates x/L₀ and y/L₀ were the most significant parameter in the 3D wave field around the breakwater, with wave height and energy varying spatially around the structure. This confirms the importance of 3D effects on wave height prediction and highlights the inadequacy of 2D models that are unable to deal with spatial variation of wave height behind the breakwater. The RBF model trained by non-dimensional parameters was determined as the most appropriate tool and was proven to be more capable of handling wave transmission prediction comparing with other ANN models. Predictions from the proposed ANN model were found to be in very good agreement with new laboratory data never seen by the model before. The ANN model predictions have also been compared with results from the MIKE 21 BW model. The proposed ANN model was validated in three distinct cases of interpolation, extrapolation and larger scale tests. The model gave the most reliable and convincing predictions within a specific range of input parameters (interpolation) while outside this range (extrapolation) to some extent, reasonable results were still achieved. The proposed model was assessed under larger scale conditions with data collected in another wave tank with different laboratory facilities. Outputs under these conditions also showed good agreement. This shows that the performance of the model is not affected significantly by scale changes and the model has the potential to be used in real applications. The Boussinesq wave model was found to overestimate wave-induced breaking dissipation over the crest of the submerged breakwater leading to underprediction of wave transmission. The evaluations showed more consistency between the measured experimental data and predictions from the ANN model in comparison to those from the Boussinesq wave model. These demonstrate the accuracy and reliability of the model and its capability in predicting the wave field around submerged breakwaters. A simplified version of the numerical model and wave prediction scheme is provided in this thesis for practical applications. The proposed ANN model is a significant advance in that it can be used to predict 3D wave pattern around submerged breakwaters in the range of dimensionless Cartesian coordinate -0.26
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Fischer, Michael P. "The function of submerged active breakwaters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22302.pdf.
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Ledermann, Thomas H. "Submerged mold casting using heat pipes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44006.pdf.
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Nicoletti, Martino. "Submerged landscapes : aesthetics of visual primitivism." Thesis, University of the West of Scotland, 2012. http://hdl.handle.net/10545/303736.
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This practice-based thesis presents the results of experimental research devoted to ethnic tourism among the Kayan minority and has involved the interconnection of artistic and anthropological languages. Known worldwide for the traditional female custom of wearing a long coiled brass necklace aimed at causing a considerable extension to the neck, the Kayan are a Tibeto-Burman ethnic group originally from Burma. Due to the prolonged civil war in their own homeland, a large number of Kayan recently fled from Burma to refuge in neighbouring Thailand. Here, over the past years, in response to the “incisive” tourism policy promoted by the Thai government in the northern areas of the country, some families, abandoning the refugee camps where they were hosted, have been resettled in several new villages open to tourists, on payment of a modest entrance fee. Here the Kayan, their culture and their daily life, have been transformed into an authentic tourist attraction capable of drawing about 10,000 visitors a year. Founded on a strictly “visual media primitivist” approach and inspired by its peculiar aesthetics – as systematically presented in the first, theoretical, section of the thesis –, the enquiry involves a multimedia perspective. In such a context, analogue photography and filmmaking, creative writing and sound composition have been combined to give concrete shape to an original artwork firmly grounded in ethnographic practice. The choice, far from being a solely arbitrary and subjective option, has indeed been motivated by the critical employment of specific theoretical assumptions of some of the most recent streams of anthropology and epistemology of the human sciences. The multidisciplinary methodology adopted to develop the research, as well as the multifaceted language employed to display its results, represent an innovative and experimental way of approaching the complex theme of cultural identity in present-day Asian contexts, as well as of highlighting the most aesthetic and philosophic implications connected to the revival of analogue vintage media in contemporary artistic practice.
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Randall, Richard John. "Fluid-structure interaction of submerged shells." Thesis, Brunel University, 1990. http://bura.brunel.ac.uk/handle/2438/5446.
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A general three-dimensional hydroelasticity theory for the evaluation of responses has been adapted to formulate hydrodynamic coefficients for submerged shell-type structures. The derivation of the theory has been presented and is placed in context with other methods of analysis. The ability of this form of analysis to offer an insight into the physical behaviour of practical systems is demonstrated. The influence of external boundaries and fluid viscosity was considered separately using a flexible cylinder as the model. When the surrounding fluid is water, viscosity was assessed to be significant for slender structural members and flexible pipes and in situations where the clearance to an outer casing was slight. To validate the three-dimensional hydroelasticity theory, predictions of resonance frequencies and mode shapes were compared, with measured data from trials undertaken in enclosed tanks. These data exhibited differences due to the position of the test structures in relation to free and fixed boundaries. The rationale of the testing programme and practical considerations of instrumentation, capture and storage of data are described in detail. At first sight a relatively unsophisticated analytical method appeared to offer better correlation with the measured data than the hydroelastic solution. This impression was mistaken, the agreement was merely fortuitous as only the hydroelastic approach is capable of reproducing-the trends recorded in the experiments. The significance of an accurate dynamic analysis using finite elements and the influence of physical factors such as buoyancy on the predicted results are also examined.
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Oladipupo, Adebisi Oladimeji. "Slag detachability from submerged arc welds." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14953.
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Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 78-80.
by Adebisi Oladimeji Oladipupo.
Sc.D.
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Page, Charlotte. "Free surface flows over submerged obstructions." Thesis, University of East Anglia, 2015. https://ueaeprints.uea.ac.uk/56892/.
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Steady and unsteady two-dimensional free surface flows subjected to one or multiple disturbances are considered. Flow configurations involving either a single fluid or two layers of fluid of different but constant densities, are examined. Both the effects of gravity and surface tension are included. Fully nonlinear boundary integral equation techniques based on Cauchy’s integral formula are used to derive integro-differential equations to model the problem. The integro-differential equations are discretised and solved iteratively using Newton’s method. Both forced solitary waves and critical flow solutions, where the flow upstream is subcritical and downstream is supercritical, are obtained. The behaviour of the forced wave is determined by the Froude and Bond numbers and the orientation of the disturbance. When a second disturbance is placed upstream in the pure gravity critical case, trapped waves have been found between the disturbances. However, when surface tension is included, trapped waves are shown only to exist for very small values of the Bond number. Instead, it is shown that the disturbance must be placed downstream in the gravity-capillary case to see trapped waves. The stability of these critical hydraulic fall solutions is examined. It is shown that the hydraulic fall is stable, but the trapped wave solutions are only stable in the pure gravity case. Critical, flexural-gravity flows, where a thin sheet of ice rests on top of the fluid are then considered. The flows in the flexural-gravity and gravity-capillary cases are shown to be similar. These similarities are investigated, and the physical significance of both configurations, examined. When two fluids are considered, the situation is more complex. The rigid lid approximation is assumed, and four types of critical flow are investigated. Trapped wave solutions are found to exist in some cases, depending on the Froude number in the lower layer.
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Kenchington, Christopher James. "The shock response of submerged masts." Thesis, University of Surrey, 1986. http://epubs.surrey.ac.uk/847588/.
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A study of the response of submerged mast-like structures to shock loads has been carried out. An analytical model has been developed which uses a lumped parameter system whose equations of motion are solved by the use of finite difference time integration techniques. The effects of the stiffness and damping inherent in the supporting restraints are successfully included into the analysis by assuming that they provide linear rotational stiffness and a viscous type of damping. An analysis of hydrodynamic interaction effects has been developed in order to investigate how the frequency response of the structure is affected by submergence. Changes in both the frequency and the damping characteristics are predicted as a function of the depth of submergence. Methods of incorporation of these hydrodynamic forces into the time domain solution of the lumped mass system are investigated and are found to be most accurate for slender structures. In order to develop a fuller understanding of the hydrodynamic response, two experimental investigations have been carried out. The first is laboratory based and uses carefully controlled free vibration tests to excite a number of modal frequencies of a rigidly clamped vertical mast in both submerged and partially submerged conditions. Results show that the frequency changes are closely predicted by the hydrodynamic analysis developed in this thesis and also show that hydrodynamic damping is a linear function of amplitude of deflection for the first natural response mode over the mast's elastic range of response. To investigate the shock response of submerged structures, a second test rig is used to subject a slender mast to a shock load radiating from an underwater explosion. The structural significance of the higher modal frequencies is evaluated through the use of Fourier Analysis and digital filtering techniques. The instrumentation performance including both damped and undamped transducers is assessed in order to make recommendations for future shock trials. The experimental investigation has shown that both the direct pressure loading and the movement of the supports are important factors in the mast response and that their combination produces important high frequency response modes.
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Fisher, Allison Lynn. "Submerged Experimentation in Middlebrow Modernist Fiction." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1298475770.
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Walsh, Michael Thomas. "Corrosion of Steel in Submerged Concrete Structures." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/6048.
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This investigation determined that severe corrosion of steel can occur in the submerged portions of reinforced concrete structures in marine environments. Field studies of decommissioned pilings from actual bridges revealed multiple instances of strong corrosion localization, showing appreciable local loss of steel cross-section. Quantitative understanding of the phenomenon and its causes was developed and articulated in the form of a predictive model. The predictive model output was consistent with both the corrosion rate estimates and the extent of corrosion localization observed in the field observations. The most likely explanation for the observed phenomena that emerged from the understanding and modeling is that cathodic reaction rates under oxygen diffusional limitation that are negligible in cases of uniform corrosion can nevertheless support substantial corrosion rates if the corrosion becomes localized. A dynamic evolution form of the model was created based on the proposition that much of the steel in the submerged concrete zone remained in the passive condition given cathodic prevention that resulted from favorable macrocell coupling with regions of the steel that had experienced corrosion first. The model output also matched observations from the field, supporting the plausibility of the proposed scenario.
The modeling also projected that corrosion in the submerged zone could be virtually eliminated via the use of sacrificial anode cathodic protection; the rate of corrosion damage progression in the low elevation zone above water could also be significantly reduced. Continuation work should be conducted to define an alternative to the prevalent limit-state i.e., visible external cracks and spalls, for submerged reinforced concrete structures. Work should also be conducted to determine the possible structural consequences of this form of corrosion and to assess the technical feasibility and cost/benefit aspects of incorporating protective anodes in new pile construction.
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Wicaksana, Filicia School of Chemical Engineering & Industrial Chemistry UNSW. "Submerged hollow fibre membranes in bubbling systems." Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2006. http://handle.unsw.edu.au/1959.4/25998.
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This study focuses on the optimisation of submerged hollow fibre membrane performance by analysing the role of air sparging on the reduction of membrane fouling. In submerged hollow fibre membranes, rising bubbles have been shown to induce shear, liquid movement and fibre displacement. The interaction between fibre movement induced by bubbling and the microfiltration performance was assessed for various parameters (fibre tightness, fibre length, fibre diameter, air flowrate, nozzle size, and feed concentration). A model feed of yeast suspension and a series of isolated fibres were used. The fibre movement was assessed by monitoring the displacement using video recording. Bubble population parameters were also measured. The results suggest that bubbleinduced fibre movement plays an important role in controlling membrane fouling. Investigations of the critical flux at various operating conditions also supported these conclusions. Since energy consumption for aeration is a major contributor to the cost in submerged membranes, the potential to minimise the aeration cost has been tested by implementing intermittent aeration and different nozzle sizes. It was found that an optimum condition associated with a low fouling rate could be reached by combining various aeration intermittencies and nozzle sizes. An attempt to suppress fouling without aeration was made by incorporating vibrations into a submerged hollow fibre membrane system. The effects of vibration frequency, type of yeast (washed and unwashed) on the filtration performance were observed. The impact of coagulant addition on filtration enhancement was also analysed. The performance of microfiltration was evaluated based on its critical flux value. The findings in this preliminary study indicated potential fouling control by applying vibrations to submerged membranes. A semi-empirical model was developed to predict the filtration behaviour by taking into account the bubble-induced shear and fibre movement. The predicted critical flux values suggested that membrane fouling appears to be more prominent at low air flowrate, with tight fibres, and higher feed concentrations. The model fits the experimental data with discrepancies from approximately 0.3% to 20%. The predicted filtration profiles at different operating modes demonstrate the importance of bubble-induced shear and fibre movement in the improvement of filtration performance.
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LANGENOJA, MARKUS, and KARLSSON VINCENT ÖHRVALL. "Next generation high productivity submerged arc welding." Thesis, KTH, Maskinkonstruktion (Inst.), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-148055.
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The task of designing concepts for the next generation of submerged arc welding heads was given by ESAB. ESAB is a global company manufacturing welding equipment for a wide span of industries and uses. In October 2011, ESAB introduced a new technology called Integrated Cold Electrode™, abbreviated and trademarked as ICE™. ICE™ is a technique which utilizes three electrodes in a highly productive and stable process. The current state of the ICE™ technique focuses on welding thick plates with conventional joint types such as x- and v-joints. The next phase in the development of the technique is to be able to weld milled 16/8°-joints which are developed by German company Graebner. This kind of joint determines the requirements of the next generation of ESAB’s equipment for submerged arc welding.Simultaneously as designing the welding torch being able to weld the 16/8°-joint, a concept for a highly customizable modular head was developed enabling the possibility to tailor the submerged arc welding process according to the customer’s precise needs.A progressive conceptual development has been conducted in close collaboration with ESAB. Theoretical models have been developed to evaluate thermal-electric behavior of the welding torches to obtain plausible dimensions for the electric conductors to withstand the effects caused by joule heating. Deliverables for the project has been well defined 3D CAD-models while a prototype was not included in the scope of the project.One concept for the 16/8° joint is presented as the Narrow Joint Concept, NJC, which fulfills the requirements specified. The NJC is developed with focus on smart design with low manufacturing cost as well as ease-of-use for the operator. NJC brings ICE™ into narrow joints.The Modular Head Concept, MHC, presents an idea how to create a fully customizable process with the possibility to emulate the ICE™ techniqueUppdraget att utveckla nästa generation pulverbågsutrustning gavs av företaget ESAB. ESAB är ett globalt företag som tillverkar svetsutrustning för ett brett spann av branscher och användningsområden. I oktober 2011 lanserade ESAB en ny teknik vid namn Integrated Cold Electrode™, ICE™. ICE™ är en teknik som utnyttjar tre stycken elektroder i en högproduktiv och stabil svetsprocess. I dagsläget fokuserar ICE™-tekniken på att svetsa konventionella fogtyper såsom x- och v-fogar i tjocka plåtar. Nästa fas i utvecklingen av tekniken är möjligheten att svetsa frästa 16/8°-fogar som det tyska företaget Graebner utvecklar. Denna typ av foggeometri ger kraven för ESAB’s nästa generation pulverbågsutrustning.Simultant togs koncept fram för att möjliggöra skräddarsydd utrustning efter kunders specifika processbehov.En progressiv konceptutveckling har utförts i nära sammarbete med ESAB. Teoretiska modeller har tagits fram för att utvärdera de termo-elektriska egenskaperna hos de utvecklade svetshuvudena så att dessa kan motstå den resistiva uppvärmningen som sker i de elektriska ledarna. Då en prototypframtagning ej låg inom ramen för arbetet har detaljerade 3D CAD-modeller producerats.Konceptet för 16/8°-fogen kallas Narrow Joint Concept, NJC, och uppfyller de uppställda kraven. NJC är framtaget med fokus på smart konstruktion där låg tillverkningskostnad och enkel användning har premierats. NJC sammanfogar ICE™ och smala fogar.Det modulära konceptet kallat Modular Head Concept, MHC, representerar en idé för att skapa skräddarsydda lösningar efter kunders behov. MHC äger förmågan att fungera som ett ICE™-huvud.
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Heyworth, Alan. "Submerged forests : a dendrochronological and palynological investigation." Thesis, Aberystwyth University, 1985. http://hdl.handle.net/2160/6594baa4-2718-46b5-8c3b-519ab870bb76.
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The distribution and nature of submerged forest beds are described, in particular those on the coasts of N.W. England, Wales, and the Bristol Channel. Present-day analogues of submerged forest vegetation are identified, and the relationship of coastal woodlands to tidal levels is discussed, as a necessary preliminary to the deduction of past sea levels, from the evidence provided by submerged forests. Experiments were carried out to determine the effect on seedling oaks of various tidal regimes of immersion in salt water. They proved to be little-affected, confirming observations of mature oaks in coastal woodlands, and suggesting that submerged forest trees grew at a lower relative level than has previously been assumed. The results of pollen analysis and radiocarbon dating of peat and wood (c3500-6000 B.P.) are given, for sites at Stolford (Bridgwater Bay, Somerset) and Clarach Bay and Borth (Cardigan Bay). Other sites are more briefly discussed, and evidence of human settlement is described. The relative dates of death of trees were determined by dendrochronological techniques, and the very precise chronology thus established is used to deduce the course of events. The extensive use of the trees in the calibration of radiocarbon dates is also described. Rapid increases in the organic content of sediments are shown to be possible when sea level rise slows to a critical rate: no fall in relative sea level need be invoked. Estimates are made of the past frequency of abnormally-high tides, and the “effective sea-level” resulting from these and other tidal effects is discussed, but the uncertainties involved are shown to be such that no great increase in the precision of determinations of past sea levels can be expected.
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woods, Clay W. "Movement of Air Through Submerged Air Vents." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1074.
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A series of physical models consisting of three different diameter pipes at the same 4% slope were studied at the Utah Water Research Laboratory (UWRL). Various combinations of air flow and head on the pipe were used to determine the effect of pipe diameter, head, and air flow on the behavior of air bubbles introduced into the pipes and to determine the venting capacity of the pipes. It was determined that neither bubble velocity nor bubble length changes with pipe diameter or head changes within the range tested. It was also determined that bubble velocity and length will increase with increased air flow. Bubble velocity also increased with increasing bubble length consistent with prior research. Overall the venting capacity of a pipe is dependent upon having a large enough pipe to prevent slug flow. A procedure was developed to aid in the sizing of submerged vent piping during the design of pipelines based on the data collected during this study and utilizing prior research.
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Tamrakar, Swaraj. "Analytical Model Study of Flow Through Trapezoidal, Half-Trapezoidal and Rectangular Channels with Submerged and Un-submerged Rigid Cylinders." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1380.
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For this study, two analytical models were developed for predicting the depth-averaged velocity distribution (U) in trapezoidal, half-trapezoidal and rectangular channels with submerged and unsubmerged rigid cylinders. The first model uses linear superposition of momentum defects (MDS) and mass conservation, and is referred to as the MDS model. The second model uses linear superposition of velocity defects (VDS) and mass conservation, and is referred to as the VDS model. For implementing either the VDS or MDS model, a criterion is required for considering the wake created by an individual cylinder to be fully dissipated (i.e., a cutoff criterion). Also, implementing the MDS model requires numerical integration. Analyses were conducted to identify suitable cutoff criterion and an appropriate subinterval size for the numerical integration. Data from a physical model study conducted in a flume with a half-trapezoidal channel section was used to calibrate and validate the models. Data from a physical model study conducted in a rectangular channel section was also used to validate the model. Predicted values of U from the VDS and MDS models were within the range of ± 20 % of the trapezoidal channel section validation data. The models failed to accurately predict U for the rectangular channel section data. It is concluded that the models developed herein should be used only for half-trapezoidal channel sections. With respect to the trapezoidal channel section validation data, the MDS model yields a sum of squared errors that is 36% less than that yielded by the VDS model. Therefore, the MDS model is regarded as the best model overall for computing U in half-trapezoidal channel sections.
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Ayala, Fernández Unai, and Luis Manuel Hernández. "Investigation of submerged maritime target detection using LIDAR." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9100.
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Lidar is an optical remote sensing technology which uses the backscattered light to create information profiles of the scanning area. Normally the air is used as propagation medium, but in this work the Lidar's efficiency to detect submerged target in water is discussed. Following the theories of light propagation in the air and in the water a model to simulate the target detection is created. The values of scattering and absorption of the laser pulse in water are estimated by Morel equations which give accurate values of the sea water properties. Scattering and absorption define the optical properties of the medium, so the attenuation and the backscattering coefficient are calculated. These value will have a strong dependency to the salinity, pressure, temperature, sea water constituents and so on. After the estimation of the parameters a model based on Lidar Equation, Fresnel Equations and Snell´s law has been developed with the aim of predict the maximum range to detect the sea surface and the maximum depth to detect the sea bottom. In order to verify the goodness of the model, a prototype 532nm Lidar system has been used to collect experimental data. The Lidar was used from a 50m high building scanning from near vertical incidence to near horizontal incidence. The extracted data from the simulations have been compared with the data obtained from realized test. This has given us a predicted maximum range to detect the sea surface of 220m and an estimated maximum depth for a reference target of 17m.
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Kadkhodabeigi, Mehdi. "Modeling of Tapping Processes in Submerged Arc Furnaces." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13240.
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Valderhaug, Aasgeir Mikael. "Modelling and control of submerged-arc ferrosilicon furnaces." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 1992. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19565.
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Brandtsegg, Andreas Saur. "Dynamic Modelling and Analysis of Submerged Floating Tunnels." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18424.
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Investigations are performed on the capabilities of Computational Fluid Dynamics (CFD) to model a transient transcritical flow around a Submerged Floating Tunnel (SFT). The aim of this inquiry is to examine the possibility of modeling the effect of Vortex Induced Vibrations (VIV) on a circular cylinder, through a coupling between a 2D CFD simulation, and a 3D FEM analysis of the structure trough strip theory. To validate such an approach, it is essential to verify that the CFD analysis yields accurate results. A simulation has been performed on the flow around a circular cylinder with Re=3.6⋅〖10〗^6, based on the solution of the 2D Unsteady Reynolds Averaged Navier-Stokes (URANS) equations with the Realizable k-ϵ turbulence model using enhanced wall treatment. The hydrodynamic values obtained is the time averaged drag coefficient (CD,avrg), the root-mean-square lift coefficient (CL,rms), and the non-dimensional shedding frequency (St). The analysis yields a St=0.26, which is within published experimental values, in contrast to published numerically obtained results.
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Caresta, Mauro Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Structural and acoustic responses of a submerged vessel." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2009. http://handle.unsw.edu.au/1959.4/44404.
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Excitation of the low frequency vibrational modes of a submerged vessel can generate significant radiated noise levels. Vibrational modes of a submarine hull are excited from the transmission of fluctuating forces through the shaft and thrust bearings due to the propeller rotating in an unsteady fluid. The focus of this work is to investigate the structural and acoustic responses of a submarine hull under axial excitation. The submarine hull is modelled as a cylindrical shell with internal bulkheads and ring stiffeners. The cylindrical shell is closed by truncated conical shells, which in turn are closed at each end using circular plates. The entire structure is submerged in a heavy fluid medium. The structural responses of the submerged vessel are calculated by solving the cylindrical shell equations of motion using a wave approach and the conical shell equations with a power series solution. The displacement normal to the surface of the structure in contact with the fluid medium was calculated by assembling the boundary/continuity matrix. The far field radiated sound pressure was then calculated by means of the Helmholtz integral. Results from the analytical model are compared with computational results from a fully coupled finite element/boundary element model. The individual and combined effects of the various influencing factors, corresponding to the ring stiffeners, bulkheads, conical end closures and fluid loading, on the structural and acoustic responses are characterised by examining the contribution by the circumferential modes. It is shown that equally spaced internal bulkheads generate a periodic structure thus creating a grouping effect for the higher circumferential modes, but do not have strong influence on the sound radiation. Stiffeners are found to have an important effect on both the dynamic and acoustic responses of the hull. The contribution of the conical end closures on the radiated sound pressure for the lowest circumferential mode numbers is also clearly observed. This work shows the importance of the bending modes when evaluating the sound pressure radiated by a submarine under harmonic excitation from the propulsion system.
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Seabrook, Stuart R. "Investigation of the performance of submerged rubblemound breakwaters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22394.pdf.
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Turek, Gabriella. "Multiple scattering from submerged bodies dissimilar acoustical properties." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/17056.
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Craig, Sally Helene. "The heterogeneity of filamentous fungi in submerged culture." Thesis, University of Manchester, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492379.
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繆泉明 and Quanming Miao. "Effect of submerged vertical structures on ship waves." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B3025176X.
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Karam, Andrew. "Chloride Ingress into Submerged Concrete Under Sustained Load." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30484.
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A harsh, cold, and icy environment is of no surprise to the conditions of a winter climate, where the wide use of de-icing salts on roads and highways allows for the initiation of chloride-induced corrosion of the reinforcement of concrete structures; a reduced service life, loss of structural integrity, visible damages, and ultimately structural failure are among the many unwanted effects of rebar corrosion. Chloride ingress into concrete has been extensively studied for the last four decades; however, most of the relevant research to date does not take into account the effects of sustained loading on chloride transport properties. Therefore, the objectives of this study were to investigate the influence of sustained compressive and tensile stresses on chloride ingress into concrete, and ultimately to understand what the effect of sustained stress is on chloride penetration depth, on chloride concentration by % weight of concrete, and on apparent diffusion coefficients by comparing results to those of unloaded control specimens.
To achieve these objectives, six post-tensioned and four non-reinforced control concrete beams were constructed with different water-to-cement (w/c) ratios and completely submerged in a 4-5% de-icing salt (NaCl) solution for 12 weeks, allowing chloride transfer to be completely governed by continuous diffusion. The effects of supplementary cementing material on chloride ingress are also studied. Concrete beams were post-tensioned to induce variable sustained compressive and tensile stresses along the beam. After 12 weeks of exposure, beams were fractured at specific locations and sprayed with a 0.1N silver nitrate (AgNO3) solution to determine average penetration depths; chloride concentration profiles were obtained from potentiometric titration of grinded powder samples.
Apparent chloride diffusion coefficients were then obtained from the results of spraying AgNO3 and titration, the latter by non-linear regression curve-fitting to Fick’s second law of diffusion. A good agreement between results from both methods reveals that the use of AgNO3 in field is acceptable in predicting the rate of chloride ingress in concrete sustaining stress. The chloride diffusivity for each profile, relative to that of the unstressed section, was related to the compressive and tensile stresses in the concrete section. The experimental results indicate the dependence of chloride ingress and concentration on the type and level of sustained stress. An analysis of the results to study the effects of the w/c ratio using colourimetric (silver nitrate spray) and potentiometric titration methods was also completed.
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Peters, Daniel Joseph. "Submerged arc welding consumables for HSLA-100 steel." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26280.
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Vaidyanathan, Seetharaman. "Monitoring submerged mycelial bioprocesses using near-infrared spectroscopy." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248359.
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McIver, M. P. "The interaction of water waves with submerged bodies." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356225.
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Absi, Alfaro Sadek Crisostomo. "Mathematical modelling of narrow gap submerged arc welding." Thesis, Cranfield University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232955.
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Schiffer, Andreas. "The response of submerged structures to underwater blast." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:4503e2e9-c712-4f8a-a6bb-9986981d56ab.
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The response of submerged structures subject to loading by underwater blast waves is governed by complex interactions between the moving or deforming structure and the surrounding fluid and these phenomena need to be thoroughly understood in order to design structural components against underwater blast. This thesis has addressed the response of simple structural systems to blast loading in shallow or deep water environment. Analytical models have been developed to examine the one-dimensional response of both water-backed and air-backed submerged rigid plates, supported by linear springs and loaded by underwater shock waves. Cavitation phenomena as well as the effect of initial static fluid pressure are explicitly included in the models and their predictions were found in excellent agreement with detailed FE simulations. Then, a novel experimental apparatus has been developed, to reproduce controlled blast loading in initially pressurised liquids. It consists of a transparent water shock tube and allows observing the structural response as well as the propagation of cavitation fronts initiated by fluid-structure interaction in a blast event. This experimental technique was then employed to explore the one-dimensional response of monolithic plates, sandwich panels and double-walled structures subject to loading by underwater shock waves. The performed experiments provide great visual insight into the cavitation process and the experimental measurements were found to be in good agreement with analytical predictions and dynamic FE results. Finally, underwater blast loading of circular elastic plates has been investigated by theoretically modelling the main phenomena of dynamic plate deformation and fluid-structure interaction. In addition, underwater shock experiments have been performed on circular composite plates and the obtained measurements were found in good correlation with the corresponding analytical predictions. The validated analytical models were then used to determine the optimal designs of circular elastic plates which maximise the resistance to underwater blast.
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Hietava, A. (Anne). "Electrical behaviour of submerged arc furnace’s charge materials." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526219394.
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Abstract When producing ferrochrome, a submerged arc furnace (SAF) is used. The charge of an SAF consists of chromite pellets, coke, lumpy ore and quartzite as a slag modifier. The charge is pre-heated before it descends into the SAF where the charge eventually reduces and melts. The electrical conductivity of the charge is important because, among other things, it affects the productivity of the furnace. The electrical conductivity of the charge should ideally be low on the higher parts of the furnace and high near the electrode tip. This is to ensure that the electric current path travels through the metal bath via arcing, which provides the most effective heat transfer. Another option for the current path would be through the solid feed material via ohmic conduction, but since this zone is less reactive, the heat energy would be mostly wasted. This work brings forth new information about the electrical behaviour of coke and chromite pellet is produced. The electrical conductivity was measured at room temperature for different simulated process conditions (different coke textures, different reduction degrees of chromite pellets, sulphur in atmosphere and replacing the coke used in chromite pellet production with charcoal). It was found out that unlike gasification with a CO/CO2 mixture, heat treatment at 950°C increased the degree of graphitization and changed the electrical behaviour of coke. Furthermore, it was observed that increasing the chromite pellets’ reduction degree reduced the electrical conductivity measured at room temperature. In the case of chromite pellets and sulphur in the atmosphere it was found that sulphur has an effect on the pellets’ electrical behavior and structure during reduction, which - in turn - has an effect on the SAF performance when raw materials with varying sulphur contents are used. Lastly, it was found that substituting coke with charcoal when producing chromite pellets affects the sintering behaviour, cold compression strength, and electrical conductivity of the chromite pelletsTiivistelmä Uppokaariuuni on osa ferrokromin valmistusprosessia. Uppokaariuuniin panostetaan kromiittipellejä, koksia, palarikastetta ja kvartsiittia. Etukuumennusuunista panos laskeutuu uppokaariuuniin, jossa se pelkistyy ja lopulta sulaa. Uppokaariuunin panoksen sähkönjohtavuus on tärkeää uunin toiminnan kannalta, koska se vaikuttaa suoraan esimerkiksi tuottavuuteen. Jotta virran kulku tapahtuisi optimaalisesti sulan metallin kautta, panoksen sähkönjohtavuuden tulee olla pieni uunin yläosissa ja suuri alaosassa lähellä elektrodien päitä. Mikäli virran kulku tapahtuu uunin yläosassa, hukataan lämpöenergiaa ja uunin toiminta hankaloituu. Tässä työssä on selvitetty koksin ja kromiittipellettien sähköisiä ominaisuuksia. Sähkönjohtavuutta on tutkittu useilla simuloiduilla prosessiolosuhteilla (koksin eri tekstuurit, kromiittipellettien eri pelkistysasteet, rikin pitoisuus atmosfäärissä ja kromiittipellettien valmistuksessa on korvattu koksi puuhiilellä). Nämä mittaukset on tehty huonelämpötilassa. Huomattiin, että toisin kuin koksin kaasutus, koksin lämpökäsittely (950°C) nosti grafitoitumisastetta ja vaikutti sähköisiin ominaisuuksiin. Kromiittipelletin pelkistymisasteen noustessa huonelämpötilassa mitattu sähkönjohtavuus laski. Kun kromiittipelletit altistetaan atmosfäärille, jossa on rikkiä, pellettien sähköiset ominaisuudet muuttuvat samoin kuin rakenne pelkistyksen aikana. Tämä vaikuttaa uppokaariuunin toimintaan, kun käytetään raaka-aineita, joissa rikkipitoisuus vaihtelee. Kun kromiittipellettien valmistuksessa käytettävä koksi korvataan puuhiilellä, tämä vaikuttaa sintrausprosessiin, kylmälujuuteen ja sähköisiin ominaisuuksiin
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Clapham, Alan John. "The characteristics of two mid-Holocene submerged forests." Thesis, Liverpool John Moores University, 1999. http://researchonline.ljmu.ac.uk/5023/.
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Miao, Quanming. "Effect of submerged vertical structures on ship waves /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23765902.
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Weiland, Christopher Jude. "Characteristics of the High Speed Gas-Liquid Interface." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26150.
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The objective of this dissertation was to investigate physical characteristics of high speed gas-liquid interfaces for the cases of subsonic, transonic, and supersonic gas jets submerged underwater and the transient development of an underwater projectile reaching the supercavitating state. These studies are motivated by the need to understand the basic physics associated with a novel submersible missile launcher termed the Water Piercing Missile Launcher (WPML).
This dissertation presents the first study of high speed round and rectangular gas jets submerged underwater utilizing a global optical measurement technique. This technique allows quantitative measurement of the entire gas jet and the interfacial motion. Experimental results indicate that the penetration of the gas jets into a quiescent liquid is strongly influenced by the injection mass flow and the nozzle geometry. In contrast, the oscillations of the interface are influenced by the injection Mach number. The transition from a momentum driven to a buoyant jet is determined using a characteristic length scale that appears to be in good agreement with experimental observations. Moreover, the unsteadiness of the interface appears to be governed by both Kevin-Helmholtz and Rayleigh-Taylor instabilities.
This dissertation also contains the first study of a projectile accelerating to reach the supercavitating state. Experimental results show that the transient development of the supercavity is governed by the formation of a vortex ring. Nuclei are shed from the forebody of the accelerating projectile and are entrained in the vortex ring core where they are subjected to low pressure and subsequently expand rapidly. A characteristic time scale for this supercavity development is presented.Ph. D.
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Tillery, Steven W. "Enhanced boiling heat transfer by submerged, vibration induced jets." Available online, Georgia Institute of Technology, 2004, 2004. http://etd.gatech.edu/theses/available/etd-07142005-161107/.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2004.Smith, Marc K., Committee Chair ; Glezer, Ari, Committee Member ; Ghiaasiaan, S. Mostafa, Committee Member. Includes bibliographical references.
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Pujol, Company M. Dolors. "Waves and turbulence on submerged and emergent aquatic vegetation." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/111336.
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Coastal zones are governed by physical forces originating from tidal currents, waves, winds and night convection, amongst others, and are characterized by the presence of canopy meadows. This thesis studies the hydrodynamic in a fluid dominated by: nearly isotropic turbulence, progressive waves and breaking waves in different canopy models. Under nearly isotropic turbulence sheltering is enhanced by a reduction in the plant-to-plant distance. Under progressive waves sheltering is associated with the reduction of wave velocity at the top of submerged rigid canopy. Sheltering observed in the submerged flexible model is caused by blade movement which absorbes the energy. Emergent rigid vegetation shows sheltering. On the other hand, for some specific progressive wave conditions and plant densities and under a fluid dominated by breaking waves, turbulence increases within the meadow if Reynolds number, based on wave velocity, is larger than 300Les zones costeres estan governades per forces físiques originades per la marea, l’onatge, i la convecció nocturna, entre d’altres, i caracteritzades per la presència de plantes aquàtiques. Aquesta tesi té per objectiu estudiar la hidrodinàmica d’un fluid dominat per: turbulència quasi-isotròpica, onades progressives i onades trencants en diferents models de vegetació. En un fluid dominat per turbulència isotròpica, la reducció de la turbulència augmenta al reduir la distància entre plantes. En un fluid dominat per onades progressives, la disminució de la turbulència està associada a la reducció de la velocitat d’onada al cim de la vegetació. Aquesta reducció s’observa en plantes submergides flexibles degut a que el moviment de les plantes absorbeix l’energia. La vegetació emergent també redueix la turbulència. Per condicions específiques d’onades progressives i densitat de plantes i sota un fluid dominat per onades trencants, la turbulència incrementa si el número de Reynolds és més gran que 300
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Tillery, Steven W. "Enhanced boiling heat transfer by submerged, vibration induced jets." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7080.
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In this analysis, the efficacy of cavitation jets for heat transfer enhancement was demonstrated. The cavitation jet was formed from a cluster of cavitation bubbles that are the result of a submerged piezoelectric diaphragms oscillating about a given velocity threshold Two different heaters operating in two different flow environments were examined. For each heater in each environment, the cavitation jet significantly increased the heat transfer
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Szymczak, Michel. "Flow visualization of cavitating, high-speed, submerged water jets." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5159.
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Voisin, Adam Francis. "Submerged vane performance in strongly curved narrow channel bends." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/6175.
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Submerged vanes are thin flow-training structures that protrude above the channel bed to a height of approximately 0.2 to 0.5 times the flow depth. They have lengths of 1 to 4 times their height, and are typically angled between 5 and 30 degrees to the free-stream flow direction (counterclockwise, when viewed in plan, in a bend turning to the right). The vanes induce a secondary current which may be harnessed to counteract the centrifugally-induced helicoidal flow in channel bends. A reduction in the strength of the helicoidal current will in turn lead to a corresponding reduction in outer bank erosion. Physical model testing was performed to determine the effects of several parameters which affect submerged vane performance, namely: submerged vane height H, length L, angle to main flow direction alpha, vane streamwise spacing deltas, vane transverse spacing from outer bank deltan, and bend angle ϕ. Two bend angles were examined in this study. The majority of testing was performed in a 90° bend, and a limited number of tests were performed in a 135° bend with the same radius. (Abstract shortened by UMI.)
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Carriveau, Edward Christian Janson. "Study of dye-core vortices at submerged water intakes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ58020.pdf.
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Hamilton, S. D. "The boundary element method for flow around submerged bodies." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375241.
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葉子良 and Tsz-leung Yip. "Active water-wave control by a submerged pitching plate." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31237976.
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Marjoribanks, Timothy Ian. "High resolution modelling of flexible submerged vegetation in rivers." Thesis, Durham University, 2013. http://etheses.dur.ac.uk/7773/.
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Vegetation is a common feature within natural river channels and exerts a profound influence on the functioning of the fluvial system. In particular, the interaction between vegetation and flow causes a reduction in conveyance, an alteration to the velocity profile and the generation of coherent turbulent structures which differ to those found in un-vegetated channels. Recognition of the influence of vegetation on open channel flow has led to an increased awareness of the importance of accurately representing the effects of vegetation within numerical models, across a range of spatial scales. This thesis introduces two novel biomechanical models, capable of simulating the complex interaction between flow and vegetation at high spatial and temporal resolution. The development and validation of these models permits investigation of flow-vegetation interactions across a range of plant types and flow conditions. These models are applied to a range of scenarios providing new insight into the interaction mechanisms between the vegetation and the flow. In particular, this thesis focuses on the role of turbulent structures in driving flow-vegetation interaction. The results presented in this thesis support existing theories for simple canopy flows, whilst also proposing additional interactions in the case of more complex canopies. In addition, key findings relating to the role of drag in controlling flow-vegetation interactions are explored. Finally, through the development of a third, lower resolution, vegetation model, this thesis begins to explore how the process understanding gained from application of the high resolution models may be upscaled to the reach scale models which are central to river management.
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Wang, Woei, and 王瑋. "Second order surface wave propagating over submerged marine trench and submerged breakwater." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/22322532686870231546.
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Liu, Chin-Chi, and 劉俊志. "Experiments studies of submerged breakwaters and submerged horizontal plate wave absorber effect." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/62789197325875843527.
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Shieh, Wei-long, and 謝偉朧. "Wave Diffraction of Submerged Structures." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/75939032033118951942.
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碩士國立成功大學
水利及海洋工程學系
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Wave diffraction by submerged structures with shapes of circular cylinders and rectangular cubes are investigated. Three dimensional experiments and 3-D boundary element numerical calculations are presented. Experiments were conducted in aplane wave basin with 36.5m long, 17.2m wide, and 0.35m of water depth. The wave periods generated by the wave maker were 0.7sec, 1.0sec, 1.3sec, and 2.0sec. The circular cylinders were constructed by piling up circular disk of 0.1m height which was made of concrete. The dimensions of the circular cylinder were 1.0m of diameter, and variable heights of 0.1m, 0.2m, 0.3m of submerged cases, and 0.4m of intruding the water surface. The rectangular cubes were constructed by piling up rectangular cubes of 1.0m long, 0.1m wide, and 0.1m height. The width of the rectangular cubes were 0.2m, 0.4m, 0.6m, and 1.0m; and the heights were 0.1m, 0.2m, 0.3m of submerged cases, and 0.4m of intruding the water surface.The experimental results were compared with numerical calculations. In the three dimensional boundary element model, constant element was used in the calculation. The Laplacian governing equation was solved along with boundary conditions for free surface boundary, bottom boundary, structural boundary, and radiation boundary. The results of numerical calculations were compared with experiments which gave better graphics of wave diffraction patterns. Results of diffraction patterns by circular cylinders and rectangular cubes were also compared and discussed. The MacCamy-Fuchs wave diffraction of a circular cylinder intruding the water surface was used to verify the accuracy of experimental results and numerical calculations. For submerged structures without wave breaking, numerical results compared favorably with experiments. Effects of the structural shapes, depth of structure submergence, as well as relative water depth on wave diffraction were studied. The results showed that the shorter the incoming wave length, the clearer the wave focusing behind the structural center, and the further the position behind. Under the same wave conditions, the rectangular structures had further wave focusing than the circular cylinders.