The late University of Canterbury civil engineering lecturer Peter Giddens developed a range of simple microhydro turbines, with publications from as early as the 1980s. He considered that a range of simple but well-designed turbines which covered the gamut of possible small sites would be more useful than any single turbine. He started with radial inflow turbines, then set about extending their range of applicability by increasing specific speed. That extension was continued by the research in this thesis, which aimed to produce a design with a minimum efficiency of 70 % at a specific speed of at least 600 (rev/min, kW, m). Achieving those targets would differentiate it from existing microhydro designs. In order to reach those performance targets, the volute, runner, and draft tube were examined through experiment and computational fluid dynamics models to characterize past designs and test the validity of their embodied assumptions. A prototype with a design specific speed of 650 was built and fully characterized by dynamometer testing. Measurements of the outlet velocity distribution of two of Peter Giddens’s volutes confirmed that single tangential inlet volutes are not torque-free when certain geometric conditions are met; swirl increased through those volutes by 70 % or more depending on the design. A new overall turbine design was proposed, where axial flow enters the runner and swirling flows leaves it. This required the design of a novel volute. Through computational analysis, the effect of swirling flow entering the conical draft tube was shown to affect its pressure recovery: negatively for draft tubes with small angles, positively for larger angles. It was shown that the peak pressure recovery of an optimum draft tube was not likely to be improved upon by the use of swirl, and since there was uncertainty in the analysis, a conservative draft tube was specified for the prototype. A flat-bladed runner was designed for the prototype and computational modeling indicated its performance would be sensitive to small changes in flow angle. Despite that sensitivity — an intrinsic property of high specific speed runner velocity triangles — the computational model was shown to give good predictions of the runner flow characteristics, although not its effciency. Finally, a 1.2 kW prototype was built and achieved a peak net effciency of 64 % as defined by the American Society of Mechanical Engineers at a net head of 2.07 m, a flowrate of 94 L/s, and a runner shaft speed of 1670 rev/min, corresponding to a specific speed of 740. Maximum measured runner efficiency of 87 % also occurred at those conditions. Compared to existing designs, that performance extended the operational envelope of microhydro turbines considerably. A three-zone computational model of the entire prototype was assembled and trialled, but not validated. It is concluded that for efficient high specific speed turbines, volute swirl characteristics must be known with confidence, as the volute sets the conditions at the leading edge for peak runner efficiency. A simple but efficient runner may be made using flat blades, showing the potential for this geometry even when made by limited workshops. Adding a free-vortex tangential velocity distribution to the inlet flow of a stalled conical draft tube may increase its pressure recovery, although it is not likely to exceed the best performance obtainable with axial inlet flow. Therefore taking measures to reduce the peak fluid velocity entering the draft tube could be more beneficial to overall performance than seeking outright improvements in draft tube pressure recovery.

Len Lye was born in Christchurch, New Zealand, in 1901. Lye was an avid enthusiast of kinetic sculpture and experimental film. In 1965 Lye built a prototype for a kinetic sculpture called Blade that he intended would be a much larger work. In 1996, Dr. Shayne Gooch of the University of Canterbury embarked on a research contract that saw the fruition of Lye’s Blade at a scale previously unachieved. This work was given the name Big Blade. This thesis provides a study into the maximum realisable scale of Blade using technology and materials available today. A new pivoting clamp design is tested and assessed using a small scale Blade sculpture built at the University of Canterbury and used as a test rig. Advancements in technology, material availability and manufacturing techniques lead to a comprehensive fatigue study of the new clamp design. Stresses are measured at the critical stress location in the blade material and a new maximum economic scale of Blade is suggested. The new sculpture requires a blade material that measures 10024mm x 1080mm x 22mm. The visible blade length is 8424mm. The new sculpture is called Giant Blade. A critical aesthetic component for Len Lye’s performance of Blade is the mode shapes formed by the blade material. Specifically, the second and third bending modes (Lye’s single and double harmonic) and the first torsional bending mode (Lye’s shimmering frequency). These frequencies are calculated using the new pivoting clamp design to ensure that these sections of the performance are maintained in Giant Blade. An important requirement of the new sculpture drive mechanism is the capability to reduce the amplitude of shuttle oscillation dynamically during Blade performances. This capability allows bending stresses in the blade material to be reduced in the third bending mode of vibration without halting the performance to adjust the shuttle oscillation amplitude. Four dynamically adjustable variable stroke mechanisms are presented and compared using the methods of Pahl and Beitz. A suitable mechanism for Giant Blade is selected and a proposed arrangement for the new sculpture is provided. An embodiment design is presented for Giant Blade. This embodiment design consists of a new pivoting clamp design and the proposed variable stroke mechanism. Further work includes the design of a mechanism to support the ball and wand assembly.

Growing concerns about the environmental impact of fossil fuel energy and improvements in both the cost and performance of wind turbine technologies has spurred a sharp expansion in wind energy generation. However, both the increasing size of wind farms and the increased contribution of wind energy to the overall electricity generation market has created new challenges. As wind farms grow in size and power density, the aerodynamic wake interactions that occur between neighboring turbines become increasingly important in characterizing the unsteady turbine loads and power output of the farm. Turbine wake interactions also impact variability of farm power generation, acting either to increase variability or decrease variability depending on the wind farm control algorithm. In this dissertation, both the unsteady vortex wake loading and the effect of wake interaction on farm power variability are investigated in order to better understand the fundamental physics that govern these processes and to better control wind farm operations to mitigate negative effects of wake interaction. The first part of the dissertation examines the effect of wake interactions between neighboring turbines on the variability in power output of a wind farm, demonstrating that turbine wake interactions can have a beneficial effect on reducing wind farm variability if the farm is properly controlled. In order to balance multiple objectives, such as maximizing farm power generation while reducing power variability, a model predictive control (MPC) technique with a novel farm power variability minimization objective function is utilized. The controller operation is influenced by a number of different time scales, including the MPC time horizon, the delay time between turbines, and the fluctuation time scales inherent in the incident wind. In the current research, a non-linear MPC technique is developed and used to investigate the effect of three time scales on wind farm operation and on variability in farm power output. The goal of the proposed controller is to explore the behavior of an "ideal" farm-level MPC controller with different wind, delay and horizon time scales and to examine the reduction of system power variability that is possible in such a controller by effective use of wake interactions. The second part of the dissertation addresses the unsteady vortex loading on a downstream turbine caused by the interaction of the turbine blades with coherent vortex structures found within the upstream turbine wake. Periodic, stochastic, and transient loads all have an impact on the lifetime of the wind turbine blades and drivetrain. Vortex cutting (or vortex chopping) is a type of stochastic load that is commonly observed when a propeller or blade passes through a vortex structure and the blade width is of the same order of magnitude as the vortex core diameter. A series of Navier-Stokes simulations of vortex cutting with and without axial flow are presented. The goal of this research is to better understand the challenging physics of vortex cutting by the blade rotor, as well as to develop a simple, physics-based, validated expression to characterize the unsteady force induced by vortex

A textura tem posição de destaque na qualidade da carne, podendo ser considerada como a característica sensorial de maior influência na aceitação por parte dos consumidores. Nesse contexto, as técnicas de determinação da textura da carne são de extrema importância. Assim, o objetivo desta dissertação foi o estudo comparativo de três técnicas de determinação da força de cisalhamento de carnes, utilizando-se dois equipamentos diferentes: o Warner-Bratzler Shear com sua lâmina padrão e um Texturômetro modelo TAXT2i (SMS) com duas lâminas de espessuras diferentes (3,05 e 1,01 mm), com a intenção de se obter correlações entre as diferentes técnicas utilizadas. Foram determinadas as forças de cisalhamento em seis cortes cárneos (5 bovinos e 1 suíno) com a finalidade de se obter as correlações numa ampla faixa de força de cisalhamento. Outras análises (Composição química, Perdas de água por cozimento e Microestrutura) foram realizadas para complementar as informações dos efeitos das três técnicas utilizadas sobre as respectivas respostas. Os dados obtidos nos testes de cisalhamento foram submetidos a uma análise descritiva visando determinar as variações entre os resultados de cada corte. A composição química, a microestrutura e as perdas de água foram utilizadas para explicar possíveis causas das variações. Foram feitas análises de regressão, obtendo-se modelos de correlação entre os dados obtidos com o Warner-Bratzler Shear e o texturômetro com as duas lâminas estudadas. Os resultados obtidos com Texturômetro utilizando-se lâmina de 3 mm superestimaram os resultados, indicando menor maciez do que as outras técnicas. Não se observou relação entre a composição química e a perda de água por cozimento com a textura das carnes. Entretanto, os resultados das análises com microscopia eletrônica de varredura permitiram explicar a variabilidade dos resultados da força de cisalhamento. / Texture has a prominent position on the quality of meat, and it can be considered the most influential sensory characteristic on consumers\' acceptance. In this sense, the techniques for texture determination of meat are very important. Thus, the aim of this dissertation was a comparative study of three techniques of determination of shear force of meat, using two different equipments: Warner-Bratzler Shear, with its standard blade; and the Texturometer TAXT2i, with two blades with different thicknesses (3.05 and 1.01 mm), for obtaining correlations between these different techniques. The shear forces were determined in six meat cuts (5 bovines and 1 swine) allowing correlations over a wide range of shear force. Other analyzes (chemical composition, water losses during cooking and microstructure) were performed to supplement the information of the effects of three techniques on shear force results. The data obtained in the shear tests were subjected to a descriptive statistical analysis in order to determine variations between the results for each cut. The chemical composition, microstructure and water losses were used to explain the possible causes of variations. Regression analyzes were performed and linear models of correlation between the data obtained with Warner-Bratzler Shear and the two blades texturometer were established. The results obtained with the 3 mm blade texturometer overestimated the results, suggesting lower softness than the other techniques. There was no relationship between the chemical composition and water loss during cooking with the meat texture. However, the results of analysis with scanning electron microscopy allowed explain the variability of the results of shear force.

Este trabalho apresenta um estudo do processo de corte de pequenas placas de piezocerâmicas usadas na fabricação de materiais piezocompósitos pelo processo de corte e preenchimento. Foi feito o projeto de uma máquina de corte com disco adiamantado de acordo com as necessidades do processo de corte e preenchimento para produzir piezocompósitos que requerem cortes tão finos quanto 30µm. A máquina utiliza um \"spindle\" com mancais aerostáticos com rotação de até 60.000 rpm para cortes com lâminas de 2 polegadas de diâmetro. Os piezocompósitos são os elementos principais na fabricação de transdutores de ultra-som, com freqüências até 10 MHz, para aplicações médicas e industriais. O estudo do corte com discos adiamantados com pequenas espessuras é baseado no modelo cinemático usado para modelar o processo de retífica por abrasão e em verificações experimentais de corte de pequenas placas de piezocerâmicas. Os resultados experimentais do corte de piezocerâmica tipo PZT com disco adiamantado são analisados com o auxílio de um microscópio óptico. São medidas as imperfeições superficiais dos cortes. / This work presents a study of the diamond blade dicing of piezoceramic slabs to fabricate piezocomposites by dicing and fill process. A diamond blade dicing machine is designed according the needs of the dicing and fill process to produce piezocomposites which requires dicing with diamond blades as thin as 30µm. The dicing machine has a high speed (up to 60.000 rpm) spindle with aerostatic bearings for 2 inches diameter dicing blades. The piezocomposites with frequency up to 10 MHz are the main part of ultrasonic transducers for medical and industrial applications. The study of thin diamond blade dicing is based in the kinematic model for grinding and experimental work. The results of diamond blade dicing of PZT piezoceramic slabs are analysed with an optical microscope and the measurements of superficial cracks are presented.

This PhD involved computational fluid dynamic simulations of finned generators cooling under forced convection in an oscillating water column environment. Various design changes to the upstream Wells turbine and its effect on the consequent cooling of the generator were investigated. Simulations were run in steady-state to obtain an initial condition, thereafter, unsteady simulations revealed a steadying of heat transfer over the course of multiple blade rotation cycles. This justified the use of steady-state for the remaining simulations over a range of flow coefficients. The results revealed that the heat transfer from the generator increased for tighter blade tip clearances, thicker blade profiles and greater turbine solidity. The heat transfer was found to increase with rising flow rate coefficient, which was adjusted by increasing the inlet velocity whilst maintaining the angular velocity of the turbine at a constant 2000 RPM. Additionally, the variation of turbine angular velocity at a fixed flow rate coefficient was investigated, the heat transfer was also found to increase with angular velocity, albeit by a far lesser extent. The inclusion of the Wells turbine upstream of the generator was investigated initially and was found to increase heat transfer due to the resulting impingement of airflow across the generator. In all design scenarios in which the heat transfer increases, there is also an observed increase in the mass flow rate of air, radially, towards the generator.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Nos Ãltimos anos, vÃrias pesquisas foram desenvolvidas na regiÃo SemiÃrida do Nordeste Brasileiro, no intuito de conhecer as potencialidades, tanto na produÃÃo como na qualidade de suas forragens. Como exemplo, a pornunÃa (Manihot sp.) na adiÃÃo de fonte de proteÃna no arraÃoamento de animais. Avaliou-se um modelo para a estimativa da Ãrea foliar, morfometria, composiÃÃo quÃmico-bromatolÃgica e mineral da pornunÃa (Manihot sp.) em funÃÃo da densidade de plantio e adubaÃÃo fosfatada. O experimento foi conduzido em sistema de sequeiro, no perÃodo de maio 2010 a outubro de 2011. Adotou-se o delineamento em blocos casualizados, em esquema fatorial 4 x 4, com trÃs repetiÃÃes, sendo 4 espaÃamentos (1,5 x 1,5; 1,5 x 2,0; 2,0 x 2,0 e 2,5 x 2,0 metros) e 4 doses de fÃsforo (0,0; 56,66; 113,32 e 169,98 gramas/covas de superfosfato simples). Foram marcadas 192 plantas, sendo 4 por parcelas para avaliaÃÃes morfomÃtricas (altura da planta, nÃmero de ramos, diÃmetro de caule e nÃmero de folhas), quÃmico-bromatolÃgica e mineral (folhas, hastes e pool). No estudo do modelo para estimativa da Ãrea foliar, foram coletadas 3 folhas por planta, num total de 144, para determinaÃÃo da AF utilizando o mÃtodo direto (AFReal), medidor de Ãrea foliar tipo esteira (Li-Cor 3100) e por meio das dimensÃes lineares. O crescimento da pornunÃa, em termos de altura da planta, nÃmero de ramos, diÃmetro de caule e nÃmero de folhas depende da distribuiÃÃo temporal dos pulsos de precipitaÃÃo, principalmente o nÃmero de folhas da planta. Dentre as variÃveis de crescimento avaliadas, o nÃmero de folhas da planta à o mais sensÃvel Ãs variaÃÃes da disponibilidade de Ãgua no solo e distribuiÃÃo da chuva na estaÃÃo chuvosa e, como consequÃncia nÃo hà efeito do espaÃamento de plantio nem da adubaÃÃo fosfatada sobre esta variÃvel. A densidade de plantio e a adubaÃÃo fosfatada nÃo influenciam o nÃmero de rebrotaÃÃes, folhas e diÃmetro da pornunÃa quando cultivada em sequeiro. Em condiÃÃes de sequeiro, o espaÃamento de plantio e a adubaÃÃo fosfatada nÃo interferem (p>0,05) na composiÃÃo quÃmico-bromatolÃgica das folhas e do pool da pornunÃa, em termos de MS, PB, FDN, CHOT e CNF a exceÃÃo do teor de EE do pool. Pelo contrario, o espaÃamento de plantio e a adubaÃÃo fosfatada afetam (p<0,05) na composiÃÃo quÃmico-bromatolÃgica das hastes, a exceÃÃo do CHOT. A adubaÃÃo fosfatada e o espaÃamento de plantio influenciam os teores de magnÃsio e fÃsforo nas hastes e fÃsforo no pool da pornunÃa. A Ãrea foliar da pornunÃa determinada pelo medidor Li-Cor 3100 à cerca de 10% inferior em comparaÃÃo ao mÃtodo AFReal. O modelo que melhor se ajusta para a estimativa da Ãrea foliar foi do tipo potencial a partir das dimensÃes morfolÃgicas se aproximarem mais quando se usa o produto da largura pelo comprimento da folha, independente do seu tamanho. / In recent years, several studies have been developed in the semiarid region of Northeast Brazil, in order to know the potential, both in production and in the quality of the fodder. As an example, pornunÃa (Manihot sp.) used as addition of a protein source in animal feeding. It was evaluated a model for leaf area estimation, morphology, chemical composition and mineral of the pornunÃa (Manihot sp.) in function of planting density and phosphorus fertilization. The experiment was conducted under rainfed system in the period from May 2010 to October 2011. It was adopted a randomized block design in a factorial 4 x 4 with three replications and four spacings row (1,5 x 1,5; 1,5 x 2,0; 2,0 x 2,0 and 2,5 x 2,0 meters) and four levels of phosphorus (0,0; 56,66; 113,32 and 169,98 grams/pits superphosphate). 192 plants were marked, being 4 by plots for morphological (plant height, number of branches, stem diameter and number of leaves), bromatological and mineral (leaves, stems and pool). In the model studies to estimate leaf area were collected 3 leaves per plant, for a total of 144 leaves, to determine the AF using the direct method (AFReal), leaf area meter (Li-Cor 3100) and by linear dimensions. The growth of pornunÃa in terms of plant height, number of branches, stem diameter, leaf number depends on the temporal distribution of precipitation pulses, particularly the number of leaves. Among the growth variables evaluated, the number of leaves of the plant is the most sensitive to changes in soil water availability and rainfall distribution during the rainy season and as a consequence there is no spacing row or phosphorus fertilization effect on this variable. Planting density and phosphorus fertilization did not influence the number of regrowth, leaves and diameter of the plant when it is grown in rainfed. Under rainfed conditions, the planting space and phosphorus fertilization do not interfere (p> 0.05) in the chemical composition of the leaves and the pool of pornunÃa, in terms of DM, CP, NDF, CHOT and NFC, with exception of EE content in the pool. Rather, the spacing row and phosphorus fertilization affect (p <0.05) the chemical composition of the stems, with the exception of CHOT. The phosphorus fertilization and planting spacing influence the levels of magnesium and phosphorus in the stems and phosphorus in the pool of the pornunÃa. The pornunÃa leaf area determined by the meter Li-Cor 3100 is about 10% lower compared to the AFReal method. The model that best fits to estimate the leaf area was the potential type from the morphological dimensions, when it gets closer if using the product of the width by length of the sheet, regardless of its size.

Este trabalho apresenta uma abordagem para a identificação da dinâmica não linear do modelo matemático de uma pá de helicóptero em rotação. Durante a simulação, foi considerado o helicóptero em voo pairado. Foi usada a representação bilinear para o modelo, uma das formas mais simples de representação de um modelo não linear. O modelo matemático da pá foi implementado através do método de elementos finitos e simulado em ambiente Matlab. Foi suada na identificação, uma rede neural artificial como técnica não convencional, já que demonstra grande capacidade de aproximação de modelos não lineares, grande desempenho em análise da dinâmica de sistemas flexíveis e implementação e rapidez consideráveis. As redes neurais com processamento temporal são usadas para aproximar componentes da dinâmica não linear sobre um conjunto de entradas prescritas, e são usadas em simulação como meio rápido de obter a resposta no tempo. Para capturar a natureza recursiva dos componentes dinâmicos do sistema foi usada uma rede feedforward com processamento temporal, com uma camada intermediária de neurônios e com entradas na rede atrasadas. Para verificar o desempenho da rede, foi feita a comparação entre os dados de simulação obtidos originalmente e os dados resultantes de simulação da rede. Este trabalho foi desenvolvido visando futuramente aplicação de técnicas de controle de vibrações em pás rotativas. / This work presents an approach for non-linear dynamics identification of a rotating helicopter blade mathematical model. During simulation, the helicopter was considered in hovering flight. A bilinear representation was used for the model, since it is known as one of the simplest forms of representation of a non linear model. Mathematical model of blade was implemented using finite elements method and simulated in Matlab. A neural network is used in the identification process as a non conventional technique, since it demonstrates good capacity for approximation non-linear models and good performance in terms of the analysis of the dynamics of flexible systems. It also presents good performance in terms of implementation and processing speed. The neural networks with time dependent processing are used to approximate the components of the non-linear dynamics over a prescribed inputs set, and they are used in simulation as a rapid way of obtaining the time response. In order to capture the recursive nature of the dynamic components of the system, a feedforward network with time dependent processing, with an intermediate layer of neurons and delayed inputs is used. The performance of the net was verified comparing the results obtained originally by simulation with those resulting from the network emulation. This work was developed in order to apply vibration control techniques to rotating blades.

Este trabalho apresenta uma abordagem para a identificação da dinâmica não linear do modelo matemático de uma pá de helicóptero em rotação. Durante a simulação, foi considerado o helicóptero em voo pairado. Foi usada a representação bilinear para o modelo, uma das formas mais simples de representação de um modelo não linear. O modelo matemático da pá foi implementado através do método de elementos finitos e simulado em ambiente Matlab. Foi suada na identificação, uma rede neural artificial como técnica não convencional, já que demonstra grande capacidade de aproximação de modelos não lineares, grande desempenho em análise da dinâmica de sistemas flexíveis e implementação e rapidez consideráveis. As redes neurais com processamento temporal são usadas para aproximar componentes da dinâmica não linear sobre um conjunto de entradas prescritas, e são usadas em simulação como meio rápido de obter a resposta no tempo. Para capturar a natureza recursiva dos componentes dinâmicos do sistema foi usada uma rede feedforward com processamento temporal, com uma camada intermediária de neurônios e com entradas na rede atrasadas. Para verificar o desempenho da rede, foi feita a comparação entre os dados de simulação obtidos originalmente e os dados resultantes de simulação da rede. Este trabalho foi desenvolvido visando futuramente aplicação de técnicas de controle de vibrações em pás rotativas. / This work presents an approach for non-linear dynamics identification of a rotating helicopter blade mathematical model. During simulation, the helicopter was considered in hovering flight. A bilinear representation was used for the model, since it is known as one of the simplest forms of representation of a non linear model. Mathematical model of blade was implemented using finite elements method and simulated in Matlab. A neural network is used in the identification process as a non conventional technique, since it demonstrates good capacity for approximation non-linear models and good performance in terms of the analysis of the dynamics of flexible systems. It also presents good performance in terms of implementation and processing speed. The neural networks with time dependent processing are used to approximate the components of the non-linear dynamics over a prescribed inputs set, and they are used in simulation as a rapid way of obtaining the time response. In order to capture the recursive nature of the dynamic components of the system, a feedforward network with time dependent processing, with an intermediate layer of neurons and delayed inputs is used. The performance of the net was verified comparing the results obtained originally by simulation with those resulting from the network emulation. This work was developed in order to apply vibration control techniques to rotating blades.

Improving the wind turbine blade design has a significant effect on the efficiency of the wind turbine. This is a challenging multi-disciplinary optimization problem. During the blade design process, the aerodynamic shapes, sizing of the structural members, and material composition must all be determined and optimized. Some previous blade design methods incorporate the wind turbine's static response with an added safety factor to account for neglected dynamic effects. Others incorporate the dynamic response, but in general is limited to a few design cases. By not fully incorporating the dynamic response of the wind turbine, the final turbine blade design is either too conservative by overemphasizing the dynamic effects or infeasible by failing to adequately account for these effects. In this work, we propose two methods which efficiently incorporate the dynamic response into the optimization routine. The first method involves iteratively calculating damage equivalent fatigue that are fixed during the optimization process. We also demonstrate the training and use of a surrogate model to efficiently estimate the fatigue damage and extreme events in the design process. This surrogate model has been generalized to be used for different rated turbines, and can predict the fatigue damage of a wind turbine with less than 5% error. In general, these alternative, more efficient methods have been shown to be an adequate replacement of the more computationally expensive method of calculating the dynamic response of the turbine within the optimization routine.