This paper focuses on thermal analysis of a direct driven hydraulic setup (DDH). DDH combines the benefits of electric with hydraulic technology in compact package with high power density, high performance and good controllability. DDH enables for reduction of parasitic losses for better fuel efficiency and lower operating costs. This one-piece housing design delivers system simplicity and lowers both installation and maintenance costs. Advantages of the presented architecture are the reduced hydraulic tubing and the amount of potential leakage points. The prediction of the thermal behavior and its management represents an open challenge for the system as temperature is a determinant parameter in terms of performance, lifespan and safety. Therefore, the electro-hydraulic model of a DDH involving a variable motor speed, fixed-displacement internal gear pump/motors was developed at system level for thermal analysis. In addition, a generic model was proposed for the electric machine, energy losses dependent on velocity, torque and temperature was validated by measurements under various operative conditions. Results of model investigation predict ricing of temperature during lifting cycle, and flattened during lowering in pimp/motor. Conclusions are drawn concerning the DDH thermal behavior.

Speed and displacement variable pumps offer a degree of freedom for process control. As a certain operation point can be supplied by different combinations of drive speed and pump displacement intelligent control strategies can address major issues like energy efficiency, process dynamics and noise level in industrial applications. This paper will provide an overview of recent research and development activities to evaluate the named potentials.

Thesis (MScEng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This work investigates methods to theoretically determine the lateral velocity distribution across a river from which factors may be derived to translate a single point velocity into average velocity for the river as a whole. A wide range of field data from vanous nvers was analysed. This produced over a hundred velocity distributions with which to compare theoretical distribution results. Four theoretical approaches were considered: the one-dimensional method (Manning's equation), a two-dimensional flow formula solved as an initial-value-problem, a two dimensional flow formula solved as a boundary-value-problem and an empirical method developed from energy principles. The one-dimensional and initial-value-problem approaches were unsuccessful. The boundary-value and empirical approach did however produce promising results. Surprisingly the analysis of the field data revealed patterns of similarity which could produce accurate results without the need of a theoretical approach. / AFRIKAANSE OPSOMMING: Metodes word ondersoek om teoreties 'n laterale snelheidsverspreiding oor 'n rivier te bepaal en sodoende 'n faktor te vind waarmee 'n gemete enkelpuntsnelheid in die rivier omgeskakel kan word na 'n gemiddelde snelheid vir die rivier in geheel. Vloeimeetdata van verskeie nviere IS geanaliseer. Sodoende is meer as 100 snelheidsverspreidings gegenereer waarmee die teorie vergelyk kon word. Vier teoretiese benaderings is gevolg: Manning se een-dimensionele vloeivergelyking, 'n twee dimensionele vloei-vergelyking opgelos met behulp van 'n beginwaarde, 'n twee dimensionele vloei-vergelyking opgelos met behulp van randwaardes, en 'n empiriese metode ontwikkel vanuit energie beginsels. Die een-dimensionele- en beginwaarde-benaderings was me suksesvol me. Die randwaarde- en empiriese benaderings het wel belowende resultate gelewer. Selfs verwerking van die gemete stroommetings het waardevolle inligting gelewer: daar bestaan duidelike ooreenkomste in die snelheidsverspreidings wat gebruik kan word om die verspreidingsfaktor mee te bereken sonder om teoretiese oplossings te soek.

Thesis (MScEng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Presented here is an Eulerian scheme for solving the unsteady pipe-flow equations. It is called the Characteristic Dissipative Petrov-Galerkin finite element algorithm. It is based on Hicks and Steffler's open-channel finite element algorithm [5]. The algorithm features a highly selective dissipative interface, which damps out spurious oscillations in the pressure field while leaving the rest of the field almost unaffected. The dissipative interface is obtained through upwinding of the test shape functions, which is controlled by the characteristic directions of the flow field at a node. The algorithm can be applied to variable grids, since the dissipative interface is locally controlled. The algorithm was applied to waterhammer problems, which included reservoir, deadend, valve and pump boundary conditions. Satisfactory results were obtained using a simple one-dimensional element with linear shape functions. / AFRIKAANSE OPSOMMING: 'n Euleriese skema word hier beskryf om die onbestendige pypvloei differensiaal vergelykings op te los. Dit word die Karakteristieke Dissiperende Petrov-Galerkin eindige element algoritme genoem. Die algoritme is gebaseer op Hicks en Steffler se oop-kanaal eindige element algoritme [5]. In hierdie algoritme word onrealistiese ossilasies in die drukveld selektief gedissipeer, sonder om die res van die veld te beinvloed. Die dissiperende koppelvlak word verkry deur stroomop weegfunksies, wat beheer word deur die karakteristieke rigtings in die vloeiveld, by 'n node. Die algoritme kan dus gebruik word op veranderbare roosters, omdat die dissiperende koppelvlak lokaal beheer word. Die algoritme was toegepas op waterslag probleme waarvan die grenskondisies reservoirs, entpunte, kleppe en pompe ingesluit het. Bevredigende resultate was verkry vir hierdie probleme, al was die geimplementeerde element een-dimensioneel met lineere vormfunksies.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, May 2016. / This thesis presents work on four problems identi ed in the Zomba Water Distribution Network. The research was carried out on the existing network infrastructure with the aim of improving e ciency by reducing Unaccounted-For Water (UFW). The rst challenge was to develop a demand model for the city based on its in uencing factors: daily and seasonal uctuations as well as population dynamics. The model was to capture demand patterns for short-term, medium-term to long-term time periods, thereby becoming an important input factor into decision making. The developed model may be employed to generate demand which can be input into the city's 10 year infrastructure expansion plan. The second problem was to explain why houses built too close to tanks are at risk of inconsistent water supply. It was found that the requirement of observing the tank elevations, helv, had been violated. As a result, the discontinued supplies occurred. Once the required tank elevation helv had been established, an extra increase in the elevation so as to accommodate a larger population was determined to be on the order of one centimeter. Third problem was to explain the continued mains pipe failures observed in the network. It was established that the main cause was the hammering e ects started through the process of manually closing ow control valves (FCVs) tted next to tanks. A possible remedy was to rather t the FCVs at joint nodes and not at the tanks. This was estimated to greatly reduce the hammering e ects, eventually turning them into minor head losses due to elbow bends. Finally, a structural approach to designing tanks that optimize the use of gravity is presented. This is an input into the infrastructure expansion planning of the city. Regardless of any design shapes they may take, tanks with height-radius, h=r, ratio of less than 1 exhibit diminished, as opposed to increased, height changes with demand changes. Such a property would ensure consistency in the pressure at the tank, allowing for delivery of the demanded load. / GR2016

Prever a hidrodinâmica das águas e a dispersão de contaminantes nos corpos dágua, principalmente em regiões costeiras, tem sido um problema a ser enfrentado por engenheiros, devido ao aumento dos impactos ambientais que envolvem as obras e a gestão da engenharia costeira. O uso de modelagem matemática como ferramenta de avaliação tornou-se imperativo para tais estudos. O principal objetivo desta Tese é fazer uma análise crítica da utilização da ferramenta de modelagem matemática na avaliação da dispersão de efluentes leves. A área de estudo engloba a RMBS, com ênfase no Sistema Estuarino de Santos / São Vicente. Para a efetivação desta análise são utilizados três modelos hidrodinâmicos - MIKE 21, POM e Delft3D. Esta abordagem apresentou significativa contribuição para as principais conclusões desta Tese e demonstrou, na prática, as diferenças na utilização dos modelos numéricos hidrodinâmicos. Os resultados dos três modelos utilizados apresentaram-se satisfatórios, sendo que os coeficientes de correlação encontrados, entre os resultados das simulações e dados de medição de campo, para o período de Verão de 2002 foram para o MIKE 21 de 0,63 (considerado 20 dias de processamento); o Delft3D de 0,80 (20 dias) e o POM de 0,70 (30 dias), para a Componente x (Componente E-W do vetor velocidade). Os resultados da modelagem com o POM e o Delft3D, comparados com os dados de medição de campo, imprimiram confiabilidade aos dados de correntes extraídos para o Ponto de Lançamento do Emissário de Santos/São Vicente. Neste ponto a máxima velocidade encontrada, na média da profundidade, foi de 0,27 m/s e, somente na superfície esta velocidade pode chegar a 0,35 m/s. Para a avaliação da dispersão da pluma deste emissário, foi utilizado o sistema especialista CORMIX e seus resultados mostraram que para velocidades de 0,27 e 0,18 m/s as diluições iniciais são superiores a 100 e que nas velocidades 0,08 e 0,12 m/s a diluição inicial é menor que 100. Julga-se que este trabalho contribuiu para a obtenção de um grau maior de conhecimento sobre as questões práticas da modelagem hidrodinâmica. Ou seja, esta contribuição é um passo fundamental para que o assunto seja visto de uma forma mais realista, mostrando e discutindo as características e limitações teóricas e práticas existentes em cada modelo utilizado, sob a ótica da engenharia. / The prediction of the hydrodynamic water circulation and pollutants dispersion, mainly in coastal areas, has been a problem that engineers have been facing. This is due to the increase environmental impacts that involve coastal engineering work and management. The usage of mathematic modeling as assessment tool is necessary for these studies. The main purpose of this Thesis consists in using hydrodynamics models in order to evaluate the hydrodynamical behavior in the region, and to study the effluents dispersion by approaching the marines pollution issue mainly concerning domestic wastewater, and petroleum byproducts leakage. The study area is located in the Central Coast of São Paulo State, named Baixada Santista. The highlighted area analyzed is Santos / São Vicente Estuarine System. Three hydrodynamics models were used - MIKE 21, POM and Delft3D. This approach presented a significant contribution for the main conclusions of this Thesis, and it shows the differences among the hydrodynamics mathematical models. The three models presented good results, the correlation coefficients that were found for the Summer of 2002 were 0.63 for MIKE 21 (considering 20 days of processing); 0.80 for Delft3D (20 days); and 0.70 for POM (30 days), for Component x (Component E-W of velocity vector). In the Point of Santos / São Vicente Outfall Discharge, the maximum depth average velocity reaches 0.27 m/s, and in first layer (surface) the velocity can reach 0.35 m/s. In the assessment of plume dispersion for this outfall, was used the software CORMIX and the results has shown initial dilution higher than 100 for the velocities of 0.27 and 0.18 m/s; and initial dilution lower than 100 for the velocities of 0.08 and 0.12 m/s. This Thesis contributed to obtain a better knowledge about hydrodynamic mathematic modeling. The research reveals a realistic point of view of the characteristics and limitations, in theoretical and practical terms, existing in each model used, from engineering perspective.

No contexto da necessidade de atracação de embarcações de maior porte em terminais portuários brasileiros, tanto privativos como públicos, considerando um aumento das exportações, intervenções de engenharia que possam significar ganhos nas dimensões das máximas embarcações permitidas podem representar substanciosos benefícios econômicos. Assim, este trabalho apresenta uma abordagem do conceito de Fundo Náutico, definido como profundidade até a qual as embarcações podem navegar sem que haja efeitos adversos na manobrabilidade das embarcações e danos no casco do navio, cujo objetivo é aumentar o calado máximo de embarcações em espaços náuticos cujo fundo apresente camadas de lama fluida. Devido às suas características reológicas, a lama fluida, de modo geral, permite que as embarcações naveguem com reduzida ou até negativa folga sob a quilha, respeitando-se o conceito estabelecido pelo Fundo Náutico. Exposta a importância sobre este conceito e suas peculiaridades relacionadas às características da lama fluida, como características reológicas e métodos para sua determinação, discutem-se as variações na espessura da camada de lama fluida e as variáveis ambientais que as condicionam, a partir de análise de levantamentos batimétricos de dupla frequência, dados densimétricos e aplicação de modelagem numérica, para a região da bacia de evolução do Complexo Portuário de Itajaí. Para esta região, observaram-se camadas de lama fluida entre 0,5 e 2,5 m, sendo que os resultados obtidos na modelagem indicam que esta variabilidade está associada ao regime de descarga sólida do rio Itajaí-açu. Além disto, a partir de uma análise comparativa entre os dados batimétricos e densimétricos, foi possível estabelecer que o fundo náutico na região pode estar associado a um valor de massa específica entre 1150 e 1200 kg/m³. / Considering the demand for mooring larger ships at Brazilian port terminals, both private and public, in a scenario of growing exports, engineering interventions that can provide improvements in the vessel\'s maximum allowed dimensions can represent significant profits. Hence, this work presents an approach of Nautical Bottom, defined as the maximum depth in which ships can navigate without significant adverse effects in ship control and maneuverability without physical damage, with the goal of raising the maximum ship draft allowed in nautical spaces with fluid mud beds. Due to its rheological properties, fluid mud, in general, allows for vessels navigate with low or negative under keel clearance, respecting the established Nautical Bottom concepts. Once highlighted the importance of these concepts, this study presents an analysis about fluid mud and Nautical Bottom concept analysis at Itajaí Port Complex (Santa Catarina, Brazil), one of the most important port areas in Brazil. This analysis was based on bathymetric surveys, density measurements and numerical modeling. In addition, fluid mud layer thickness at port areas can possibly vary according to hydrodynamics and sedimentologic variations. Fluid mud layer thickness varies from 0.5 to 2.5 meters at Itajai Port Complex turning basin. From numerical modeling results, it is possible to establish that the thickness variations of fluid mud layers are associated with fluvial sediment transport rates. Also, from the comparison between low frequencies bathymetric surveys and specific density measurements, it was possible to conclude that the reference specific density at the interest area is about 1150-1200 kg/m³, being very similar to reference densities adopted worldwide.

\"Chovia desde o dia 16, aumentando a intensidade das chuvas a partir das 18 horas do dia 17. As primeiras barreiras começaram a ceder nas primeiras horas da manhã do dia 18 e, às 13 horas, mobilizou-se a totalidade da avalanche\" - (CRUZ, 1974). A descrição do cenário catastrófico no Município de Caraguatatuba, no mês de Março de 1967, que resultou em um dos maiores desastres naturais ocorridos no Brasil (*), fomenta a discussão sobre as probabilidades de ocorrência de eventos pluviométricos e/ou elevações do nível do mar nas Zonas Costeiras. Diante dessa realidade, surgiu essa Dissertação, que abordou aspectos hidrológicos, hidráulicos marítimos e, estatísticos, baseados em dados pretéritos de pluviômetros e marégrafos da região do Litoral Norte do Estado de São Paulo. Foram obtidos resultados práticos para futuros projetos de macro-drenagem, obras fluviais e marítimas, que associam a probabilidade de ocorrência conjugada de determinadas chuvas, com correspondentes elevações dos níveis de maré. Também foram realizados estudos da evolução desses eventos conjugados, ao longo de sessenta anos. - (*) De acordo com informações de Cruz (1974), 436 mortes foram registradas oficialmente, 400 casas destruídas, 3.000 desabrigados numa população total de 15.000 habitantes. Foram formados depósitos de 4 m a 5 m de altura no Rio Santo Antônio com blocos entre 30 t e 100 t. / \"It was raining since March 16th, increasing the intensity of the rainfall at 6:00 pm on March 17th. The first slopes started to sag in the first hours of March 18th, at 1:00 pm, occurred all the debris-flow\" - (translated from CRUZ, 1974). The catastrophic scenario of the city of Caraguatatuba, in March of 1967, previously described, resulted from one of the most serious natural disasters in Brazil. It fosters discussions about probabilities of rainfall events and /or rise in the sea level in coastal areas. Hence, this research is a consequence of this reality, which approached hydrological, hydraulic and statistical areas, based on past data of rainfall stations and tidal stations in the region of the North Coastal Zone of the State of São Paulo (Brazil). Practical results were used for future designs of macro- drainage, fluvial and maritime projects, that associate the probability of occurrence of certain types of rainfall coupled with their corresponding increase in tidal levels. There were also evaluated studies of the evolution of these events combined over sixty years.

Com a urbanização crescente nas cidades e o aumento do escoamento superficial tornou-se necessário a implantação de reservatórios de controle de cheias, também conhecidos como \"piscinões\", capaz de reter os volumes excedentes e amortecer a vazão de pico do sistema de drenagem. A maior dificuldade na implantação deste sistema está na falta de disponibilidade de espaço físico. A associação das estruturas hidráulicas componentes dos reservatórios de controle de cheias como estruturas de controle, descarregadores de fundo e dissipadores de energia contribuem para um melhor desempenho de todo o sistema diante da ocorrência de um evento de cheia. A pesquisa realiza uma análise do estudo das principais estruturas hidráulicas utilizadas nos reservatórios de controle de cheias, assim como os critérios de projeto e dimensionamento. O estudo de caso desenvolvido no reservatório Aricanduva V em São Paulo propõe uma verificação do dimensionamento da estrutura de engolimento composta por um vertedor de soleira lateral e uma retro-análise do comportamento do conjunto vertedouro-reservatório-bacia de dissipação a partir de eventos de chuva observados. / With the increasing urbanization in the cities and the increase of the superficial draining the implantation of reservoirs of control of full became necessary, also known as \"piscinões\", capable to hold back the exceeding volumes and to cushion the outflow of peak of the draining system. The biggest difficulty in the implantation of this system is in the lack of availability of physical space. The association of the component hydraulic structures of the reservoirs of control of full as: of control spendthrift and, structures unloaders deep of energy contribute all for one better performance of the system ahead of the occurrence of an event of full. The research carries through a analysis of the main used hydraulic structures in the reservoirs of control of full, as well as the sizing and project criteria. The study of case developed in the reservoir Aricanduva V at São Paulo it considers a verification of the sizing of the composed structure of side weir and an backward-analysis of the hydraulic behavior of joint spillway-reservoir-basin of waste from the observed rain\'s events.