Šiame darbe tiriama švarių paviršių paruošimo sūkuriniu pulsuojančiu srautu galimybė. Darbo tikslas: išsiaiškinti švarių paviršių paruošimo galimybę, naudojant vandens srautą, kuriame turbulencijos lėtėjimo dėka sukeliama kavitacija. Darbas sudarytas iš keturių dalių. Pradžioje apibūdinami švarūs paviršiai, jų klasifikacija. Toliau apžvelgiami švarių paviršių paruošimo metodai, problemos. Po to, skaitmeninės simuliacijos būdu, tiriamos sūkurinį pulsuojantį srautą generuojančių purkštukų konstrukcijos. Eksperimentinėje dalyje pateikiami bandymo rezultatai, kuomet iš aliumininės plokštelės šalinamos abrazyvo liekanos, įstrigusios paviršiuje šlifavimo metu. Darbo pabaigoje pateikiamos išvados. Darbo apimtis – 51 psl. teksto be priedų, 36 iliustracijos, 3 lentelės, 13 bibliografinių šaltinių. Atskirai pridedami darbo priedai. / This study investigates the preparation of clean surfaces with pulsating vortex flow option. The aim of work: to determine the possibility of clean surface preparation using a water flow with generated cavitation. The work consists of four parts. At the start of the work characterized clean surfaces and their classification. The following provides an overview of clean surface preparation methods, problems. After that, the digital simulation method investigated vortex-generating jets pulsating flow structures. In the experimental part are presented the test results, when the aluminum plate is disposed abrasive residues trapped on the surface of the grinding time. At the end of the work there are given conclusions. Work size - 51 text pages without appendixes, 36 figures, 3 tables, 13 bibliographical sources.

[pt] O objetivo principal do trabalho consiste na análise de problemas de fluxo sob uma ótica integrada através de simulações numéricas. Tal perspectiva vêm ganhando grande atenção por parte de profissionais da área, pois permite uma abordagem mais representativa dos processos da natureza. O programa utilizado, Mike SHE, desenvolvido pelo Instituto de Hidráulica Dinamarquês, é criado num esquema determinístico e distribuído e utiliza o método das diferenças finitas como solução. O programa simula o fluxo na superfície, canais e nas zonas saturada e não saturada. No primeiro exemplo, simulou-se a interação entre um aquífero de baixa profundidade e um rio. No segundo, verificou-se a resposta do escoamento superficial submetido a variações metereológicas e fisiográficas. Ambos casos foram validados por soluções analíticas. No terceiro, realizou-se uma simulação integrada em uma escala regional para compreensão da resposta dinâmica entre os diversos armazenamentos e através de uma ferramenta de pós- processamento, calculou-se o balanço hídrico. Por fim, avaliou-se a resposta da bacia hidrográfica do Quitite e Papagaio, localizada no maciço da Tijuca, Rio de Janeiro, mediante registros de picos de precipitação anuais. As análises integradas foram satisfatórias comparando-se a modelagens individuais. O acoplamento é explícito, permitindo a inserção de passos de tempo convenientes com cada ambiente. Por fim, a abordagem integrada permitiu que os modelos dos quatro casos fossem calibrados de acordo com parâmetros de cada ambiente hidrogeológico, aumentando a confiabilidade das simulações. / [en] This master thesis aims the analysis of flow problems under an integrated approach through numerical flow modelling. The relevance of this perspective has been increasing steadily, since it allows a more representative assessment of the nature processes. The program used, named Mike SHE, developed by the Danish Hydraulic Institute, was created in a deterministic and distributed approach solved by finite difference method. The program is comprised of modules, each representing a storage: surface, channels, vadose and saturated zone. The first analysis comprise the interaction between an aquifer of low depth and a river. In the second example, it was verified the response of flow in a surface subjected to variation of physiografic and metereological parameters. Both examples were validated with analytical solutions. In the third case, an integrated simulation was carried on in order to understand the dynamic feedback generated between the storages and through a post-processing tool the water balance was calculated. The last example, assess the response the Quitite and Papagaio basin, located in the Tijuca s massif in the city of Rio de Janeiro, over high precipitation rate. The results were satisfactory in comparison of an individual flow analysis. The coupling is explicit, allowing the input of suitable time steps for each storage. Lastly, the integrated approach allowed the model setup in the four cases to be calibrated under parameters of each storage, enhancing the reliability of them.

Nedbrytning av organiskt material är en nyckelfaktor som påverkar omvandlingar av de många grundämnen som utgör eller är associerade till just organiskt material. En stor del av nedbrytningen av akvatiskt organiskt material (OM) sker i gränsskiktet mellan sediment och vatten. Eftersom så många biogeokemiska cykler styrs av nedbrytningen av OM är det viktigt att ha kunskap om processer och påverkansfaktorer både på mikro- och makronivå. Mineraliseringshastigheten av OM är en vanligt förekommande mätparameter, men vanligtvis inkluderar mätningarna inte de naturliga processer som kan påverka nedbrytnings-hastigheterna, t.ex. fysiska krafter. Syftet med den här studien är att studera mineraliseringshastigheten av det OM som finns naturligt i ytsediment i söt- och brackvatten när det utsätts för fysiska krafter som orsakar förändringar i redox-förhållanden, resuspension eller advektivt porvattenflöde. Fem laborativa experiment har utförts för att belysa syftet: Åldrat ytsediment från en sötvattens å utsattes för olika redox förhållanden där oxisk respiration, sulfatreduktion respektive metanogenes gynnades. Resultaten visade ingen skillnad i mineraliseringshastighet beroende på behandling. Detta motsäger studier utförda i marina miljöer, där anoxiska förhållanden ger en lägre mineraliseringshastighet än oxiska. Vidare gjordes två studier på brackvattensediment där effekten av resuspension var i centrum. Den ena studien fokuserade på frekvens och varaktighet av resuspensionstiderna, den andra på olika typer av sediment. Studierna visade att väldigt korta resuspensionstider med upp till 48 timmars stillhet mellan varje resuspension ökade mineraliseringstakten med fem gånger jämfört med diffusivt utbyte, och mer än dubblerades i jämförelse med kontinuerlig resuspension eller resuspension i långa perioder. Resuspensionen under kort tid var troligen gynnande då resuspension fysiskt stör bildningen av stabila bakteriesamhällen. Mineraliseringshastigheterna i sediment som domineras av väldigt fin, fin eller medium sand visade lika hastigheter, medan grov sand visade en signifikant lägre mineraliseringshastighet. Likheterna mellan de tre första sedimenttyperna kan dock ha påverkats av tillgång på lättnedbrytbart OM då sediment och vatten hämtades in under en algblomning. Till sist studerades effekten på mineraliseringshastigheten av advektivt porvattenflöde. Detta gjordes på åldrat sediment dels från en sötvattensbäck dels från en brackvattenstrand. Inget av de två sedimenttyperna visade någon skillnad i mineraliseringshastighet i jämförelse med diffusivt styrda system. Det är i motsats till tidigare marina studier, men är i linje med den första studien, där mineraliseringshastigheten var oberoende av redox-förhållande. Den generella slutsatsen från den här studien är nödvändigheten att studera samma aspekter i olika typer av akvatiska system, eftersom responsen verkar vara annorlunda beroende på system, t.ex. söt- brack- och saltvatten. Faktorer som kan förklara de här skillnaderna finns ännu inte, vilket gör att småskaliga studier och modeller blir viktiga verktyg för att utreda detta. / Organic matter mineralisation is a key parameter that affects most other element transformations associated with organic matter. A substantial part of aquatic organic matter (OM) mineralisation takes place at the interface between sediment and water. Understanding OM mineralisation is important at both the micro and macro scales, since it drives many biogeochemical cycles. OM mineralisation rates are widely measured, but generally not all the natural factors possibly affecting the rates, such as physical forcing, are considered. This thesis examines the mineralisation rates of indigenous OM in fresh and brackish surface sediments, subjected to different physical forces inducing changed redox conditions, resuspension, and advective pore water flow. Five experiments were performed to this end. Aged surface sediment from a freshwater river was subjected to different redox conditions favouring oxic respiration, sulphate reduction, and methanogenesis, respectively. Results indicated no difference in mineralisation rate irrespective of treatment. This contradicts what has been found in marine environments, where anoxic mineralisation rates are lower than oxic ones. Further, two studies of resuspension of brackish sediments were performed, one addressing the impact of the frequency and duration of the resuspension events, and the other addressing the impact of resuspension on different types of sediments. The studies found that very brief resuspension events followed by calm periods of up to 48 h increased mineralisation rates by five times compared to diffusion, and more than doubled the rate compared to continuous or long-term resuspension. The short-term events were possibly favoured because resuspension physically disturbs the arrangement of a stable bacteria community. Mineralisation rates on sediments dominated by very fine, fine, or medium-grained sand were the same, while coarse sand displayed a significantly lower rate. The similar rates of the three first sediment types could stem from access to labile OM, due to an ongoing algae bloom when the sediment and water samples were collected. Finally, the effect of advective pore water flow on aged sediment from one fresh and one brackish sediment was studied. Neither of the sediments displayed a mineralisation rate different from those occurring in incubations in which only diffusive exchange occurred. This contradicts the findings of previous marine studies, but is in line with the first study, which did not detect different mineralisation rates irrespective of redox conditions. The general conclusion is that it is necessary to study the same physical forces in different aquatic environments, since responses appear to differ, for example, between freshwater, brackish, and marine environments. Factors explaining these differences have not yet been expressed, making small-scale studies and modelling a challenge for future research.

My thesis deals with the collecting of basic information and data on riparian vegetation in surroundings of the minor watecourse Rosička through field research and subsequent inventory. In the theoretical part, I outlined the theme of watercourses and their modifications, revitalization and solutions. I also focused on vegetation accompaniment of the flows and their typology. I described the riparian and associated vegetation in detail, focused on their functions and establishment and on taking care of them. The final section of the thesis includes data of my field research. Here can be found the current condition of the species structure and the state of health of the riparian vegetation.

Le but de cette thèse est l'optimisation du contrôle commande d'un système hydraulique réversible à vitesse variable. L'approche est d'abord traitée par simulation dynamique pour finir ensuite par validation expérimentale sur maquette physique temps réel hybride basée sur l'émulation (PHIL). La partie simulation concerne la modélisation des différents éléments de la microcentrale hydraulique tel que la turbine, la génératrice et l'interface d'électronique de puissance ainsi que le développement des lois de commande et la synthèse des différents régulateurs. Deux stratégie de contrôle ont été étudié, la première dite commande en vitesse associé à un algorithme MPPT adaptatif développé au cours de la thèse et la deuxième dite en puissance. Le management des contrôles commandes pour assurer la fonction de secours (backup) de la microcentrale hydraulique a été simulé et validé expérimentalement. Et enfin la transition rapide entre les deux modes de fonctionnement d'une petite station de transfert d'énergie par pompage a été proposé et validé par émulation sur la maquette physique. / The purpose of this thesis is to optimize the control command of a reversible variable speed hydraulic system. The approach is first treated by dynamic simulation and then finish by experimental validation on hybrid physical model based on real-time emulation (PHIL). The simulation part concerns the modeling of different elements such as micro-hydro turbine, generator and the power electronics interface and the development of control laws and synthesis of different regulators. Two control strategies were studied, the first so-called speed control associated with an adaptive MPPT algorithm developed during the thesis and the second strategy is based on power control. Management controls to ensure failover (backup) of the micro-hydro has been simulated and validated experimentally. And finally the rapid transition between the two modes of operation of a small variable speed pumped storage was proposed and validated by emulation on the physical model.

Despite being one of the most productive ecosystems on earth, wetland areas have been heavily affected by human activities. The Cienaga Grande de Santa Marta (CGSM) in Colombia is one of these wetlands, where the inadequate construction of roads modified the hydrology and connectivity of this water body, generating massive mangrove mortality episodes. The lack of knowledge on the hydrological processes and connectivity of the CGSM has impaired mangrove restoration plans. Here we use wetland interferometry technique to remotely monitor the wetland and understand the flow of water in/out and across the CGSM wetland complex. A close collaboration with Miami University allowed us to access CGSM’s interferograms created with ALOS Palsar satellite data (from 2007 until 2011). The interferograms resulting from the analysis were correlated with daily hydrological data (precipitation, runoff in the main inflow of freshwater to the wetland, tide charts) to finally identify two main paths of inflow of water that are still active and are continuously feeding freshwater into the Cienaga. The most persistent was identified in the south-west part of the CGSM; a water flow coming directly from the Magdalena River and entering the main lagoon in its south-west corner. The second was located in the north-west area, where most of the mangroves have died. In this case, different interferograms showed different potential water flow paths depending on the season (dry / wet season), the Magdalena River’s discharge and the rainfall. These results reflect the complex hydrology of the CGSM . Furthermore, a coherence analysis was conducted to assess the quality of the remote sensing data and to better understand the different responses of the features within the Cienaga. The results showed that the coherence analysis could also be potentially used to identify areas of dead mangrove. This study confirms that despite the blockage of the connectivity of the wetlands, there are still important freshwater flow paths feeding the CGSM. Additional hydrological studies are needed to ensure the further understanding of the hydrology of the CGSM and confirm the results of this study.

A demanda alimentar vem aumentando de acordo com o crescimento populacional e com isso há uma necessidade de que as práticas agrícolas tornem-se cada vez mais intensas e tecnificadas, mediante o incremento, entre outros, da utilização de insumos químicos. Porém, uma vez aplicados de maneira desorganizada, sem a devida preocupação com os possíveis impactos aos recursos naturais, tais produtos podem vir a provocar danos ao solo, contaminação de águas subterrâneas (mediante sua lixiviação) e em alguns casos, podem ser responsáveis pelo aumento da salinidade em alguns solos da região do semiárido do nordeste brasileiro. Nesse sentido, devido ao fato de envolverem processos físicos na natureza, o estudo da dinâmica desses produtos químicos têm motivado diversos pesquisadores a aplicarem ferramentas matemáticas (modelos matemáticos) na área de engenharia de água e solo, buscando entender a correlação entre a dinâmica da água e o movimento de solutos no perfil do solo. Portanto, a presente pesquisa tem como objetivo a aplicação do modelo matemático HYDRUS-1D para a simulação do movimento da água e do íon potássio, em condições de laboratório, utilizando-se colunas preenchidas com dois tipos de material de solos salinos e não saturados: Argissolo Amarelo (S1) e Latossolo Vermelho Amarelo (S2). Além disso, buscou-se também avaliar tanto o desempenho do referido modelo, em condições salinas, quanto proceder a uma análise de sensibilidade. Para alcançar tais objetivos, foram conduzidas as seguintes etapas: 1) elaboração de curvas de distribuição de efluentes (Breakthrough Curves - BTC) para obtenção dos parâmetros de transporte do íon potássio, com a aplicação de soluções de 1000 ppm, 2000 ppm e 3000 ppm de concentração de potássio, nos dois tipos de solos salinos, 2) Aplicação dessas soluções de potássio na coluna preenchida com o mesmo material de solo salino não saturado, 3) Simulação dos perfis de água e potássio para os diferentes materiais de solo salino pelo modelo HYDRUS-1D e 4) Avaliação de desempenho e análise de sensibilidade do modelo HYDRUS-1D. A avaliação de desempenho foi feita levando-se em conta os seguintes índices estatísticos: erro máximo, erro absoluto médio, raiz quadrada do erro médio normalizado, coeficiente de massa residual, coeficiente de determinação, eficiência e índice de concordância de Willmott e a análise de sensibilidade foi feita mediante a determinação do erro padrão, por meio de variações positivas (+ 10%, + 20%, + 30%, + 40%, + 50%) e negativas (- 10%, - 20%, - 10%, - 40%, - 50%), dos valores de: umidade volumétrica do solo saturado, condutividade hidráulica e os parâmetros n e ? do modelo de van Genuchten (1980). Diante dos resultados obtidos, pôde-se perceber que os procedimentos experimentais (BTC\'s) para a estimativa dos parâmetros de transporte do íon potássio em condições de solo salino, foram suficientes para descrever a movimentação do íon potássio no solo, gerando informações de entrada precisas para os modelos de simulação. Em termos do modelo HYDRUS-1D, observou-se que o deslocamento do íon potássio acompanhou a frente de molhamento e que o modelo foi eficiente nas simulações de deslocamento do íon potássio e da água para ambos os solos, em condições salinas. A análise de sensibilidade evidenciou que o modelo apresentou-se sensível, às variações negativas dos dados de entrada: umidade volumétrica do solo saturado, condutividade hidráulica do solo saturado e parâmetros \"n\" e \"?\" do modelo de van Genuchten (1980). / The increased demand for food due to population growth requires that agricultural practices become increasingly intensive and very technical, including the increased use of agricultural chemicals (fertilizers). If improperly applied without considering possible impacts on natural resources, agricultural chemicals may lead to soil and groundwater contamination through their leaching from the soil root zone. They may be responsible also for increased salinity in some soils of semiarid regions in northeastern Brazil. Since many transient physical and chemical processes affect their transport in the subsurface, mathematical models have become popular tools in soil and water engineering and management in order to understand the correlation between water dynamics and solute movement in soils. Thus, this research aimed at using the HYDRUS-1D software package to simulate water and potassium movement, under laboratory conditions, in unsaturated saline soil columns filled with two soil types: an Ultisol (S1) and an Oxisol (S2). Comparisons were made with experimental data while also a sensitivity analysis was carried out to evaluate the effect of various parameters on solute transport under saline conditions. For this purpose the following studies were performed: 1) Measurement of solute breakthrough curves (BTCs) to estimate the transport parameters of the potassium ion by applying potassium solutions of 1,000 ppm, 2,000 ppm and 3,000 ppm to both soil types, 2) Application of similar potassium solutions to columns containing the same saline unsaturated soils, 3) Simulation of water and potassium distributions for different saline soil materials using HYDRUS-1D, and 4) Performance evaluation and sensitivity analyses of the HYDRUS-1D numerical model. The performance evaluation was conducted using the following statistical indices: maximum error, mean absolute error, normalized root mean square error, coefficient of residual mass, coefficient of determination, efficiency and Willmott\'s concordance index. The sensitivity analyses considered standard deviations resulting from positive and negative changes (+ 10% + 20% + 30% + 40% + 50%) (-10%, -20%, -10%, -40%, -50%) in the values of the saturated volumetric soil moisture content, the saturated hydraulic conductivity, and the parameters n and ? of van Genuchten\'s (1980) model for the unsaturated soil hydraulic functions. Results indicate that the experimental procedures (BTCs) for estimating the transport parameters of potassium for saline soil conditions were sufficient to describe potassium ion transport in the soils by generating the required input information for the simulation models. Relative to HYDRUS-1D model, the displacement of potassium was found to follow closely the wetting front, with the model providing a very efficient means for simulating the movement of both water and potassium in the two soils during saline conditions. The sensitivity analysis showed that the model was relatively sensitive to negative variations of the input data, notably the saturated water content, the saturated hydraulic conductivity, and the n and ? soil hydraulic parameters.

Orientador: Antonio Carlos Bannwart / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-07-31T15:13:41Z (GMT). No. of bitstreams: 1 ObregonVara_RosaMaribel_M.pdf: 3876695 bytes, checksum: eab8e9bdc7ff92684aba33d3163bff1a (MD5) Previous issue date: 2001 / Resumo: Considerados de grande importância na indústria petroleira, os óleos pesados constituem uma grande reserva a ser explotada e produzida. Devido a dificuldades associadas às propriedades do óleo como densidade e viscosidade, tem-se procurado métodos para produzí-lo e transportá-lo de forma econômica. Uma dessas técnicas é o corejIow, que é basicamente a injeção lateral de pequenas quantidades de água, com o fim de lubrificar o óleo, formando uma configuração concêntrica anular, onde o óleo ocupa o centro e a água a parte externa. Neste trabalho fizeram-se testes experimentaispara obter diversas informaçõessobre os padrões de fluxo em duto horizontal de um escoamento óleo pesado - água, com ênfase no padrão corejIow. Estabeleceuse uma análise de estabilidade unidimensional geral para o padrão anular liquido - líquido horizontal, através da qual chegou-se a um critério geral de estabilidade, o qual inclui o critério de Kelvin-Helmhotz, conseguindo representar bem os resultados experimentais. Os dados coletados no laboratório também permitiram desenvolver um modelo para cálculo das perdas de pressão e da fração volumétrica com correlações que consideram os fenômenos fisicos relevantes: turbulência do anel, escorregamento entre as fases, molhabilidade e rugosidade da parede e as ondulações no núcleo de óleo. O uso do corejIow consegueu reduzir a perda de pressão em até 225 vezes em comparação com o óleo sozinho / Abstract: Heavy oi! has a growingimportancein the oi! industry,given the amountof its largeand unexploited reserves. Because of the natural difficulties reIated to its physical properties - higb viscosity and density - researchhas been focusedon how to produce and transportheavyoi] economically. Oneofthemostpromisingtecbniquesinvestigated, nownascore-annularflow 01 coreflow, is based on the lateral injection of few amounts of water, so as to lubricate the oil and form an annular liquid-liquid flow pattern, with the oi! in the center, surrounded by a watel annulus. In this work, experiments were performed in a horizontal pipe, in order to obtain detailed information on different heavy oil-water flow patterns, with special interest on the core flow pattern. A one- dimensional approach to the stability ofhorizontalliquid-liquid annular flow was developed and a general stability criterion was derived, which incIudes the Kelvin-HelInholtz criterion as a special case, and gives good agreement with the laboratory measurements. The data coIlected also allowed to develop pressure drop and holdup models taking into account alI relevant physical phenomena: annulus turbulence, slip between the phases, wall wettability and roughness and interface waviness. In the present experiments, pressure drop was reduced up to 225 fold in core flow compared with the flow of an equal amount of the oi! / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

This thesis deals with revitalization of the selected part of river Drevnice. Main scopes of the work are proposals of fish passages through migration barriers. The work is conceived on four levels. The first of them is dealing with the general characteristics of selected segment and with description of objects on watercourse. The second level is dealing with revitalization, where the basic information about migration and efficiency of fishes are described. In this chapter basic distribution of fish ladders is included. In third part, which is the most comprehensive, I design a boulder fish ramp and bypass channel. The last chapter contains drawings documentation of watercourse Drevnice and my own proposed revitalization elements.

This study aims to investigate short-to-medium forecasting and simulation of streamflow, water levels, and sediments in Canada using Seasonal Autoregressive Integrated Moving Average (SARIMA) time series models. The methodology can account for linear trends in the time series that may result from climate and environmental changes. A Universal Canadian forecast Application using python web interface was developed to generate short-term forecasts using SARIMA. The Akaike information criteria was used as performance criteria for generating efficient SARIMA models. The developed models were validated by analyzing the residuals. Several stations from the Canadian Hydrometric Database (HYDAT) displaying a linear upward or downward trend were identified to validate the methodology. Trends were detected using the Man-Kendall test. The Nash-Sutcliffe efficiency coefficients (Nash ad Sutcliffe, 1970) of the developed models indicate that they are acceptable. The models can be used for short term (1 to 7 days) and medium-term (7 days to six months) forecasting of streamflow, water levels and sediments at all Canadian hydrometric stations. Such a forecast can be used for water resources management and help mitigate the effects of floods and droughts. The models can also be used to generate long time-series that can be used to test the performance of water resources systems. Finally, we have automated the process of analysis, model-building and forecasting streamflow, water levels, and sediments by building a python-based application easily extendable and user-friendly. Therefore, automating the SARIMA calibration and forecasting process for all Canadian stations for the HYDAT database will prove to be a very useful tool for decision-makers and other entities in the field of hydrological study.