[ES] El resalto hidráulico constituye uno de los fenómenos más complejos con aplicación en el campo de la ingeniería hidráulica. Por un lado, las propias características del resalto, entre las que se encuentran las grandes fluctuaciones turbulentas, la intensa entrada de aire y una disipación de energía muy significativa, contribuyen a su complejidad situando el conocimiento actual del fenómeno lejos de una comprensión total del mismo. Por otro lado, es precisamente la naturaleza disipadora de energía del resalto la que da lugar a su principal aplicación práctica. Así pues, la investigación que aquí se presenta trata de contribuir al conocimiento general del resalto hidráulico y su aplicación para disipar energía en cuencos amortiguadores de grandes presas. Para ello, se abordaron las bases del fenómeno mediante la caracterización de un resalto hidráulico clásico (RHC). La investigación se llevó a cabo bajo una doble perspectiva de modelación numérica y física. Se emplearon técnicas de Dinámica de Fluidos Computacional (DFC) para la realización de simulaciones de este resalto hidráulico, a la vez que se llevó a cabo una campaña experimental en un modelo físico específicamente diseñado para tratar el caso. De este modo, se abordaron los aspectos más relevantes del resalto hidráulico, incluyendo el ratio de calados conjugados, la eficiencia del resalto, la longitud de la zona de recirculación, el perfil de la lámina libre, las distribuciones de velocidad y presión, la longitud del resalto y el análisis de frecuencias. Los resultados de los modelos físico y numérico fueron comparados, no solo entre ellos, sino también con información de otros autores procedente de una extensa revisión bibliográfica. Ambos modelos mostraron su capacidad para representar con precisión el fenómeno estudiado. En base a este análisis se observa que la metodología empleada resulta adecuada para la investigación del fenómeno a estudiar. Una vez llevada a cabo la caracterización del RHC, se procedió a analizar un cuenco amortiguador para disipación de energía. En particular, se estudió un caso general y representativo de cuenco amortiguador tipificado USBR II, a partir de la doble perspectiva de modelación física y numérica. Asimismo, los resultados se compararon con datos y expresiones bibliográficas. Esta comparación pretendía evaluar los rasgos particulares del resalto hidráulico en cuencos amortiguadores de grandes presas, así como la influencia de los elementos disipadores de energía en el flujo. Todos los resultados mostraron estar en la línea de las investigaciones de otros autores, más allá de ciertas diferencias relativamente pequeñas. En consecuencia, la metodología desarrollada muestra su utilidad para abordar el estudio del flujo en cuencos amortiguadores. En concreto, los resultados presentados contribuyen a expandir el conocimiento sobre el RHC y el flujo en un cuenco amortiguador tipificado USBR II. Así pues, los resultados pueden emplearse para mejorar el diseño de estructuras de disipación de energía en grandes presas. Durante los últimos años, la adaptación de cuencos amortiguadores a caudales superiores a los empleados para su diseño ha ganado gran relevancia. Esta adaptación resulta clave por los efectos del cambio climáticos y las crecientes exigencias de la sociedad en materia de seguridad y protección frente a avenidas. De este modo, toda contribución a la modelación de resaltos hidráulicos, como la que aquí se presenta, resulta crucial para afrontar el reto de la adaptación de las estructuras hidráulicas para disipación de energía. / [EN] The hydraulic jump constitutes one of the most complex phenomena with application in hydraulic engineering. On the one hand, a series of features bound to the hydraulic jump nature, such as the large turbulent fluctuations, the intense air entrainment and the significant energy dissipation, contribute to build its complexity, which places the current knowledge far from a full understanding of the phenomenon. On the other hand, it is precisely this energy dissipating nature that justifies its use in large-dam stilling basins, which constitutes its main practical application. Hence, the research here presented aimed to contribute to the general knowledge of the hydraulic jump phenomenon and its application for energy dissipation purposes in large-dam stilling basins. To this end, the bases of the phenomenon were addressed by characterising a classical hydraulic jump (CHJ). The research was conducted under a double numerical and physical modelling approach. Computational Fluid Dynamics (CFD) techniques were employed to simulate the hydraulic jump, whereas an experimental campaign in a physical model designed for the purpose was carried out too. The most relevant hydraulic jump characteristics were investigated, including sequent depths ratio, hydraulic jump efficiency, roller length, free surface profile, distributions of velocity and pressure, hydraulic jump length and fluctuating variables. The results from the physical and the numerical models were compared not only between them, but also with bibliographic information coming from an extensive literature review. It was found that both modelling approaches were able to accurately represent the phenomenon under study. Once the characterisation of the CHJ was carried out, the analysis of an energy dissipation stilling basin was developed. In particular, a general and representative case study consisting in a typified USBR II stilling basin was analysed through a physical and numerical modelling approach. In addition, the modelled results were compared with data and expressions coming from a bibliographic review. This comparison was intended to assess the particular characteristics of the hydraulic jump in a large-dam stilling basin, as well as the affection of the energy dissipation devices to the flow. The results revealed not only similarities to the CHJ, but also the influence of the energy dissipation devices existing in the stilling basin, all in good agreement with bibliographic information, despite some slight differences. Consequently, the presented modelling approach showed to be a useful tool to address free surface flows occurring in stilling basins. In particular, the results reported contribute to the enhancement of the knowledge concerning the CHJ and the flow in a typified USBR II stilling basin. These results can be used to improve the design of large-dam energy dissipation structures. This is a key issue in hydraulic engineering, especially in the recent years. Thus, there is an increasing urgency for the adaptation of existing stilling basins, which must cope with higher discharges than those considered in their original design. The adaptation of these structures becomes even more important due to climate change effects and increasing society demands regarding security and flood protection. In these terms, contributions to hydraulic jump modelling, as the ones presented in this research, are crucial to face the challenge of energy dissipation structures adaptation. / [CA] El ressalt hidràulic constitueix un dels fenòmens de major complexitat amb aplicació en el camp de l'enginyeria hidràulica. D'una banda, les característiques del propi ressalt, com poden ser les grans fluctuacions turbulentes, la intensa entrada d'aire i una dissipació d'energia molt significativa, contribueixen a la seua complexitat, de manera que el coneixement actual del ressalt està lluny d'una comprensió total del mateix. D'altra banda, és precisament la gran dissipació d'energia associada al ressalt la que motiva la seua principal aplicació pràctica. La investigació que ací es presenta tracta de contribuir al coneixement general del ressalt hidràulic i la seua aplicació per dissipar energia al vas esmorteïdor de grans preses. En primer lloc, s'abordaren les bases del fenomen mitjançant la caracterització d'un ressalt hidràulic clàssic (RHC). La investigació es va dur a terme sota una doble perspectiva de modelització física i numèrica. El ressalt hidràulic es va simular emprant tècniques de Dinàmica de Fluids Computacional (DFC), mentre paral·lelament es desenvolupava una campanya experimental amb un model físic específicament dissenyat per tractar aquest cas. D'aquesta manera, es van abordar els aspectes més rellevants del ressalt, incloent el ràtio de calats conjugats, l'eficiència, la llargària de la regió de recirculació, el perfil de la superfície lliure, les distribucions de velocitat i pressió, la llargària del ressalt i l'anàlisi de freqüències. Els resultats dels models físic i numèric es compararen, no solament entre ells, sinó també amb informació procedent d'una extensa revisió bibliogràfica. Ambdós models van mostrar la seua capacitat per reproduir amb precisió el fenomen estudiat. Prenent aquest anàlisi, s'observa que la metodologia desenvolupada resulta apropiada per investigar fenòmens com el ressalt hidràulic. Caracteritzat el RHC, s'analitzà un vas esmorteïdor amb funció dissipadora d'energia. Concretament, s'estudià un cas general i representatiu de vas esmorteïdor tipificat USBR II, partint de la doble perspectiva de modelització física i numèrica. Així mateix, els resultats es van comparar amb dades i expressions bibliogràfiques. Aquesta comparació pretenia avaluar les particularitats del ressalt hidràulic al vas esmorteïdor de grans preses, així com la influència al flux dels elements dissipadors d'energia. D'aquesta manera, els resultats es situaren en la línia d'investigacions d'altes autors, més enllà de les lleugeres diferències reportades. En conseqüència, la metodologia desenvolupada mostra la seua utilitat per abordar l'estudi del flux en estructures de dissipació d'energia. En particular, els resultats contribueixen a expandir el coneixement relatiu al RHC i al flux en un vas esmorteïdor tipificat USBR II. Així, aquests resultats poden ser utilitzats per millorar el disseny de les estructures de dissipació d'energia de grans preses. Durant els últims anys, l'adaptació de vasos esmorteïdors a cabals superiors als considerats en la seua fase de disseny ha guanyat especial rellevància. Aquesta adaptació resulta crucial pels efectes del canvi climàtic i les creixents demandes de la societat en matèria de seguretat i protecció front a inundacions. En definitiva, tota contribució a la modelització de ressalts hidràulics, com la que ací es presenta, és de gran importància per afrontar el repte de l'adaptació d'estructures hidràuliques dissipadores d'energia. / The research here presented was funded by ‘Generalitat Valenciana predoctoral grants (Grant number [2015/7521])’, in collaboration with the European Social Funds and by the research project ‘La aireación del flujo y su implementación en prototipo para la mejora de la disipación de energía de la lámina vertiente por resalto hidráulico en distintos tipos de presas’ (BIA2017-85412-C2-1-R), funded by the Spanish Ministry of Economy in cooperation with European FEDER funds. / Macián Pérez, JF. (2020). Numerical and physical modelling approaches to the study of the hydraulic jump and its application in large-dam stilling basins [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149565

The main goal of this study is to define the technique to be used to assess the aggradation (by bed load) and degradation (of sediments) of the recessed as well as non-recessed stilling basins of rectangular cross section; when the hydraulic jump occurs in the stilling basin where the submergence coefficient equals 1,05. It consists of two parts, theoretical and experimental. The theoretical part summarizes the related theory on a hydraulic jump, design of a stilling basin, an incipient motion of sediment, an assessment of silting and scouring of the stilling basin. The second part, the actual experiment, led to the determination of the critical values essential for the assessment. For the evaluation, the nondimensional shear stress and the densimetric Froude number were used.

O dimensionamento das câmaras dissipadoras para válvulas dispersoras demanda um estudo sobre a interação da operação destes elementos, não somente para um ponto de operação, mas também para a faixa operativa do conjunto, que compreende a faixa de operação da válvula e da câmara de dissipação. Os limites sobre responsabilidade assumem um cenário onde as dimensões da câmara podem não ser adequadas à operação da válvula, e vice-versa. Isto porque durante o processo de dissipação de energia, ocorrem grandes turbulências que podem gerar erosão na estrutura dissipadora. A interação entre a operação das válvulas dispersoras e as dimensões da câmara dissipadora é complexa porque o dimensionamento de um elemento está associado ao outro. Assim, as dimensões necessárias para dissipação de energia na câmara dependem de dados da válvula, resultando em uma interdependência de dados para a dissipação de energia adequada. O dimensionamento do conjunto deve levar em consideração a interdependência de operação dos elementos, caso contrário o funcionamento do sistema poderá ser inadequado devido às turbulências e altas velocidades, que podem gerar cavitação e erosão das estruturas dissipadoras. Os danos na estrutura dissipadora podem causar paradas de geração de energia das usinas hidrelétricas e acidentes nas regiões localizadas a jusante desta estrutura. O dimensionamento adequado do conjunto válvula e câmara dissipadora e o conhecimento de sua faixa operativa admissível pode ser feito com auxílio de simulações numéricas e ensaios em modelo reduzido de forma a prever o comportamento adequado do protótipo. Desta forma, as simulações numéricas em CFD possibilitam maior seletividade dos casos que serão ensaiados em modelo reduzido, proporcionando maior assertividade nestes ensaios. / The sizing of valves and chambers for dissipating purpose demands a study about the interaction between these elements, not only from an operation point of view but also the whole operating range of the set, which comprehends the operating range of the valve and the dissipating chamber. The limits of liability assume a scenario where the dimensions of the chamber may be not suitable for operation of the valve, and vice-versa. This is because during dissipating energy process, major turbulences occur which may cause erosion in the dissipating structure. The interaction between the dissipating valve and the dissipating chamber dimensions is complex because the sizing of an element is associated to other. Thus, the required dimensions to dissipate energy on the chamber rely on valve data, resulting in data interdependency required for adequate energy dissipation. The set sizing must consider the operation interdependency of both elements otherwise the system operation may be inadequate due to turbulence high flow velocities, which may cause cavitation and erosion of the dissipating structures. Damages on the dissipating structure may cause energy generation interruption of hydroelectric power plants and accidents on the regions located downstream this structure. The adequate sizing of the set valve and dissipating chamber as well as the information regarding its operating range can be done with the aid of numerical simulations and physical model tests in order to predict the behavior of the prototype. Therefore, numerical simulations in CFD allow more selectivity of the cases which will be tested in a physical model, proportioning higher assertiveness on those tests.

O dimensionamento das câmaras dissipadoras para válvulas dispersoras demanda um estudo sobre a interação da operação destes elementos, não somente para um ponto de operação, mas também para a faixa operativa do conjunto, que compreende a faixa de operação da válvula e da câmara de dissipação. Os limites sobre responsabilidade assumem um cenário onde as dimensões da câmara podem não ser adequadas à operação da válvula, e vice-versa. Isto porque durante o processo de dissipação de energia, ocorrem grandes turbulências que podem gerar erosão na estrutura dissipadora. A interação entre a operação das válvulas dispersoras e as dimensões da câmara dissipadora é complexa porque o dimensionamento de um elemento está associado ao outro. Assim, as dimensões necessárias para dissipação de energia na câmara dependem de dados da válvula, resultando em uma interdependência de dados para a dissipação de energia adequada. O dimensionamento do conjunto deve levar em consideração a interdependência de operação dos elementos, caso contrário o funcionamento do sistema poderá ser inadequado devido às turbulências e altas velocidades, que podem gerar cavitação e erosão das estruturas dissipadoras. Os danos na estrutura dissipadora podem causar paradas de geração de energia das usinas hidrelétricas e acidentes nas regiões localizadas a jusante desta estrutura. O dimensionamento adequado do conjunto válvula e câmara dissipadora e o conhecimento de sua faixa operativa admissível pode ser feito com auxílio de simulações numéricas e ensaios em modelo reduzido de forma a prever o comportamento adequado do protótipo. Desta forma, as simulações numéricas em CFD possibilitam maior seletividade dos casos que serão ensaiados em modelo reduzido, proporcionando maior assertividade nestes ensaios. / The sizing of valves and chambers for dissipating purpose demands a study about the interaction between these elements, not only from an operation point of view but also the whole operating range of the set, which comprehends the operating range of the valve and the dissipating chamber. The limits of liability assume a scenario where the dimensions of the chamber may be not suitable for operation of the valve, and vice-versa. This is because during dissipating energy process, major turbulences occur which may cause erosion in the dissipating structure. The interaction between the dissipating valve and the dissipating chamber dimensions is complex because the sizing of an element is associated to other. Thus, the required dimensions to dissipate energy on the chamber rely on valve data, resulting in data interdependency required for adequate energy dissipation. The set sizing must consider the operation interdependency of both elements otherwise the system operation may be inadequate due to turbulence high flow velocities, which may cause cavitation and erosion of the dissipating structures. Damages on the dissipating structure may cause energy generation interruption of hydroelectric power plants and accidents on the regions located downstream this structure. The adequate sizing of the set valve and dissipating chamber as well as the information regarding its operating range can be done with the aid of numerical simulations and physical model tests in order to predict the behavior of the prototype. Therefore, numerical simulations in CFD allow more selectivity of the cases which will be tested in a physical model, proportioning higher assertiveness on those tests.

The thesis is dealing with comparing dissipation of the kinetic energy water flow using various bottom elements based on model research. There is missing information about efficiency of different kinds of bottom elements. This absence does not allow to compare different modification of the bottom of stilling basins. Within experimental research were measured depths in different variants. Based on the results of model tests are evaluated and tabulated sorted variants of the combat efficiency of the kinetic energy water flow. The results will be used for the efficient and economic design of additional alterations of stilling basins.

This diploma thesis, called „Reconstruction of the small water reservoir Hradisko in the cadastral area of Radslavice“, focuses on the complex process of a reconstruction of the small water reservoir Hradisko. This work follows up on the bachelor’s thesis, in which the current state of the Hradisko reservoir was described in detail. Based on the survey of the dam and the flood using a GPS device, detailed project documentation was prepared. Within the solution for the reconstruction of Hradisko reservoir, a repair of the dam and the increase of the crown of the dam is proposed, new functional objects are dimensioned, the bottom is cleared of mud, including modifications in the flood, and other necessary steps for proper functioning of the crumbling no longer compliant reservoir are described. Functional objects are processed for two variants of the solution. The first option consists of the design of a bottom outlet and a safety spillway, and the second alternative involves the design of a combined functional block. In the end, the total costs of both options are quantified and compared on the basis of an indicative item budget.

This thesis deals with the design of small reservoirs at Vyškov na Moravě. Projected reservoirs’ dams are earth-fill and homogenous and each one is equipped with the bottom water outlet and the emergency spillway. The first reservoir, located on the tributary of the Drnůvka river, has the fountain type emergency spillway and the feed pipe bottom water outlet. The reservoir of the Merchanice river, situated at the Vyškov airport, is equipped with the lateral emergency spillway and the feed pipe bottom water outlet. The third design is the reconstruction of the Marchanka reservoir projecting the dam raise. For this small reservoir two variants of functional installations were elaborated.

The subject of the thesis is to develop a simplified documentation of multipurpose reservoirs in the cadastral territory Třebařov. This thesis consists of the text, graphic and hydraulic calculations.

Die jüngst beobachteten Hochwasserereignisse zogen eine Überarbeitung der hydrologischen Daten zahlreicher Talsperren nach sich. Im Ergebnis wiesen viele der Anlagen nicht die erforderliche Hochwassersicherheit auf. Aus diesem Grund ist auch für die in Sachsen gelegene Talsperre Lehnmühle eine Ertüchtigung der Hochwasserentlastungsanlage geplant. Die Vorzugsvariante zur Wiederherstellung der Überflutungssicherheit sieht die Absenkung der Wehrkrone einzelner Überlauffelder vor. Die damit verbundene Leistungssteigerung erfordert eine Überprüfung der Abflussverhältnisse im nachgeschalteten Tosbecken. Im Rahmen der Arbeit werden die Strömungsverhältnisse im bestehenden Tosbecken mit Hilfe dreidimensionaler numerischer Modellierungen abgebildet. Mit dem Ziel einer verbesserten Energieumwandlung wird darüber hinaus die Wirksamkeit von Prallblöcken untersucht und bewertet.:1 Einleitung 2 Grundlagen der numerischen Strömungsberechnung 2.1 Numerische Modellierung im Vergleich 2.1.1 Prinzip der numerischen Strömungsberechnung 2.1.2 Exkurs: Physikalische Modellierung 2.1.3 Vor- und Nachteile der numerischen und physikalischen Modellierung 2.2 Vollständige Navier-Stokes-Gleichungen 2.3 Berechnungsmethoden 2.4 Turbulenzmodellierung 2.4.1 k-ε-Modell 2.4.2 k-ω-Modell 2.4.3 SST-Modell 2.5 Diskretisierung 2.5.1 Definieren der Geometrie 2.5.2 Berechnungsnetze 2.5.2.1 Strukturierte Netze 2.5.2.2 Unstrukturierte Netze 2.5.2.3 Hybride Netze 2.5.3 Räumliche Diskretisierung 2.5.4 Zeitliche Diskretisierung 2.5.5 Anfangs- und Randbedingungen 2.6 Wichtige Eigenschaften numerischer Berechnungsverfahren 3 Hochwasserentlastungsanlagen 3.1 Funktion 3.2 Begrifflichkeiten und Regelwerke 3.3 Aufbau 3.3.1 Einlaufbauwerk 3.3.2 Transportbauwerk 3.3.3 Energieumwandlungsanlagen 3.3.3.1 Der Prozess der Energieumwandlung 3.3.3.2 Konstruktionsmöglichkeiten 3.4 Hydraulische Bemessung 3.4.1 Hochwasserbemessungsfälle 3.4.2 Bemessungsabflüsse und Überschreitungswahrscheinlichkeiten 3.4.3 Freibordbemessung 4 Methodik 4.1Die Talsperre Lehnmühle 4.2Hydrologie 4.3Untersuchungsumfang 4.4Erstellung der numerischen Modelle 4.4.1Geometrie 4.4.1.1Wehrüberfall 4.4.1.2Tosbecken 4.4.1.3Tosbeckeneinbauten 4.4.2Numerische Modelle 4.4.2.1Modell des Wehrüberfalls 4.4.2.2Modell des Tosbeckens 4.4.3Berechnungsnetze 4.4.4Modellkonfiguration 5Ergebnisse der numerischen Berechnungen 5.1Numerik versus Physik 5.2Überfallmodellierungen 5.2.1Sensitivitätsuntersuchungen 5.2.2Ermittlung der Eingangsbedingungen für die Tosbeckenmodellierung 5.3Szenario 1 - Modellierung des bestehenden Tosbeckens 5.3.1Ergebnisse 5.3.2Sensitivitätsuntersuchungen 5.3.2.1Plausibilisierung der Randbedingung für die überströmte Tosbeckenwand 5.3.2.2Einfluss der Turbulenzmodellierung 5.3.2.3Einfluss der Rauigkeit 5.4Tosbeckenoptimierung 5.4.1Grundlegende Aussagen 5.4.2Wasserspiegellagen 5.4.3Fließgeschwindigkeiten 5.4.4Abfluss über die Tosbeckenwand 5.4.5Schubspannungen / Recent flood events called for a revision of hydrological data for numerous dams. As a result, many constructions have been found to not possess necessary flood safety. On this account, the flood spillway of the Saxon Lehnmühle dam is designated to be upgraded. In order to ensure an overflow-proof construction, the favored solution is to lower the crest of several weir fields. The resulting increased performance requires a revision of the runoff characteristics in the stilling basin. Firstly, this thesis shows the flow conditions of the existing stilling basin, using 3D numerical modeling. Secondly, with the goal of enhanced energy dissipation the effectiveness of baffle blocks will be examined and evaluated.:1 Einleitung 2 Grundlagen der numerischen Strömungsberechnung 2.1 Numerische Modellierung im Vergleich 2.1.1 Prinzip der numerischen Strömungsberechnung 2.1.2 Exkurs: Physikalische Modellierung 2.1.3 Vor- und Nachteile der numerischen und physikalischen Modellierung 2.2 Vollständige Navier-Stokes-Gleichungen 2.3 Berechnungsmethoden 2.4 Turbulenzmodellierung 2.4.1 k-ε-Modell 2.4.2 k-ω-Modell 2.4.3 SST-Modell 2.5 Diskretisierung 2.5.1 Definieren der Geometrie 2.5.2 Berechnungsnetze 2.5.2.1 Strukturierte Netze 2.5.2.2 Unstrukturierte Netze 2.5.2.3 Hybride Netze 2.5.3 Räumliche Diskretisierung 2.5.4 Zeitliche Diskretisierung 2.5.5 Anfangs- und Randbedingungen 2.6 Wichtige Eigenschaften numerischer Berechnungsverfahren 3 Hochwasserentlastungsanlagen 3.1 Funktion 3.2 Begrifflichkeiten und Regelwerke 3.3 Aufbau 3.3.1 Einlaufbauwerk 3.3.2 Transportbauwerk 3.3.3 Energieumwandlungsanlagen 3.3.3.1 Der Prozess der Energieumwandlung 3.3.3.2 Konstruktionsmöglichkeiten 3.4 Hydraulische Bemessung 3.4.1 Hochwasserbemessungsfälle 3.4.2 Bemessungsabflüsse und Überschreitungswahrscheinlichkeiten 3.4.3 Freibordbemessung 4 Methodik 4.1Die Talsperre Lehnmühle 4.2Hydrologie 4.3Untersuchungsumfang 4.4Erstellung der numerischen Modelle 4.4.1Geometrie 4.4.1.1Wehrüberfall 4.4.1.2Tosbecken 4.4.1.3Tosbeckeneinbauten 4.4.2Numerische Modelle 4.4.2.1Modell des Wehrüberfalls 4.4.2.2Modell des Tosbeckens 4.4.3Berechnungsnetze 4.4.4Modellkonfiguration 5Ergebnisse der numerischen Berechnungen 5.1Numerik versus Physik 5.2Überfallmodellierungen 5.2.1Sensitivitätsuntersuchungen 5.2.2Ermittlung der Eingangsbedingungen für die Tosbeckenmodellierung 5.3Szenario 1 - Modellierung des bestehenden Tosbeckens 5.3.1Ergebnisse 5.3.2Sensitivitätsuntersuchungen 5.3.2.1Plausibilisierung der Randbedingung für die überströmte Tosbeckenwand 5.3.2.2Einfluss der Turbulenzmodellierung 5.3.2.3Einfluss der Rauigkeit 5.4Tosbeckenoptimierung 5.4.1Grundlegende Aussagen 5.4.2Wasserspiegellagen 5.4.3Fließgeschwindigkeiten 5.4.4Abfluss über die Tosbeckenwand 5.4.5Schubspannungen

Em aproveitamentos hídricos, onde podem estar envolvidas elevadas alturas de água armazenada, o vertedouro é a estrutura hidráulica responsável por conduzir com segurança o escoamento que excede a capacidade de armazenamento do reservatório. Neste aspecto, é necessário considerar o processo de dissipação de energia a fim de proteger o pé da barragem e a própria estrutura do vertedouro contra a ação erosiva da água. Este fluxo que é descarregado é usualmente amortecido por um colchão d’água, o qual é delimitado em uma bacia de dissipação projetada com intuito de resistir aos esforços impostos pelo escoamento. Em grandes barramentos, a utilização de um vertedouro tipo salto esqui, que é caracterizado por um defletor de fluxo no final de sua calha, possibilita que não haja necessidade de revestir o leito próximo do pé da barragem, pois a incidência do jato lançado ocorre distante deste local. Desta maneira, a dissipação da energia é efetuada sobre o próprio leito do rio, sendo formada uma fossa de erosão, contudo, dependendo da resistência do leito e de suas características anisotrópicas, os padrões de recirculação do fluxo podem fazer a fossa evoluir para uma situação nociva. Por isso, desde a fase de projeto desse tipo de vertedouro, monitoramento e previsões da progressão da fossa são essenciais. Então, conforme proposta deste trabalho, abordou-se cada fenômeno que influencia no potencial erosivo do jato, como a turbulência em sua emissão e o grau de difusão do mesmo no colchão d’água. Assim, com ensaios sobre modelo físico, foi possível desenvolver duas metodologias, aplicáveis tanto para a verificação da erosão de material granular na superfície de leitos, quanto para o interior de leitos rochosos fissurados, cujas forças atuantes em um bloco de rocha isolado, podem vencer seu peso submerso e o destacar da matriz. / In hydroelectric plants, which may be involved elevated heights of stored water, the dam spillway is responsible for safely flow the water that exceeds the storage capacity of the reservoir. In this respect, it is necessary to consider the process of energy dissipation in order to protect the base of the dam and the spillway structure itself against the erosive action of the water. This stream discharged is usually cushioned by a waterbed, which is bounded into a stilling basin designed with the purpose of resist the efforts imposed by the flow. In large dams, the use of a ski jump spillway type, which is characterized by a flow deflector at the end of its chute, allows no need lining the bed near the foot of the dam, since the impact of the jet is launched away this location. Thus, the energy dissipation is performed on the riverbed itself, generating a scour hole, however, depending on the resistance of the bed and its anisotropic features, patterns of flow recirculation can evolve the pit into a harmful state. For this reason, since the design phase of this type of spillway, monitoring and predicting the progression of the pit are essential. Then, according to the proposal of this work, it was dealt with each phenomenon that influences the erosive potential of the jet, as the turbulence at its issue on the air, and the level of its diffusion of on waterbed. Based on physical model tests, it was possible to develop two methodologies, applicable both for verifying erosion of granular material from the surface of the bottom, as for analyze the interior of a fissured bedrock, which the forces acting on an isolated block of rock can overcome its submerged weight and uplift it off the matrix.