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.

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.

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.

The subject of the thesis is to design proposal protective water management solution reservoirs in the basin Kobylí potok. This thesis consist of the text, hydraulic calculation and graphic.

Tesis por compendio / The new legal regulations derived from climate change dictate that hydraulic structures must be designed to handle flood events associated with return periods up to 10,000 years. This obviously involves adapting the existing infrastructure to meet such requirements. In order to avoid risks in the restitution of the flow discharged to rivers, such as bank overflows or streambed erosion and scour processes, hydraulic design must be supported by reliable tools capable of reproducing the behavior of hydraulic structures. In the work presented herein, a fully three-dimensional CFD model to reproduce the behavior of different types of air-water flow in hydraulic structures is presented. The flow is assumed to be turbulent, isotropic and incompressible. Several RANS turbulence models are tested and structured rectangular meshes are employed to discretize the analyzed domain. The presence of two fluids is modeled using different VOF approaches and simulations are run using the PIMPLE algorithm. The model is implemented using the open-source platform OpenFOAM and its performance is compared to the commercial code FLOW-3D. The analysis is conducted separately on two different parts of hydraulic structures, namely: the spillway and the stilling basin. Additionally, a case of practical application, where the model reproduces the flow of a real-life case, is also presented in order to prove the suitability of the model to actual design cases. Mesh independence and model validation using experimental data are checked in the results of all the case studies. The sensitivity of the presented model to certain parameters is extensively discussed using different indicator variables. Among these parameters are turbulence closure, discretization scheme, surface tracking approach, CFD code or boundary conditions. Pros and contras of each of them are addressed. The analyzed turbulence models are the Standard k ¿ ¿, the Realizable k ¿ ¿, the RNG k ¿ ¿, and the SST k ¿ ¿. The discretization schemes under study are: a first-order upwind method, the second-order limited Van Leer method, and a second-order limited central difference method. The VOF approaches analyzed are the Partial VOF, as implemented in OpenFOAM, and the TruVOF, as implemented in FLOW-3D. In most cases, the Standard k ¿ ¿ model provides the most accurate estimations of water free surface profiles, although the rest of variables, with few exceptions, are better predicted by the RNG k ¿ ¿. The latter model generally requires slightly longer computation times. The SST k ¿ ¿ reproduces correctly the phenomena under study, although it generally turned out to be less accurate than its k ¿ ¿ counterparts. As regards the comparison among VOF approaches and codes, it is impossible to determine which one performs best. E.g. OpenFOAM, using the Partial VOF, managed to reproduce the in- ternal hydraulic jump structure and all derived variables better than FLOW-3D, using the TruVOF, although the latter seems to capture better the momentum transfer and so all derived variables. In the case of flow in stepped spillways, OpenFOAM captures better the velocity profiles, although FLOW-3D is more accurate when estimating the water free surface profile. It is worth remark- ing that not even their response to certain model parameters is comparable. E.g. FLOW-3D is significantly less sensitive to mesh refinement than OpenFOAM. Given the result accuracy achieved in all cases, the proposed model is fully applicable to more complex design cases, where stilling basins, stepped spillways and hydraulic structures in general must be investigated. / Las nuevas disposiciones legales derivadas del cambio climático dictaminan que las estructuras hidráulicas sean capaces de funcionar correctamente con eventos de inundación asociados a periodos de retorno de hasta 10,000 años. Esto, obviamente, implica adaptar la infraestructura existente para satisfacer dichos requerimientos. A fin de evitar riesgos en la restitución de los caudales vertidos al río, como desbordamientos o procesos erosivos y de socavación, el diseño hidráulico ha de sustentarse en herramientas fiables capaces de reproducir el comportamiento de las estructuras hidráulicas. En este trabajo, se presenta un modelo numérico CFD completamente tridimensional para reproducir el comportamiento de diferentes tipos de flujo aire-agua en estructuras hidráulicas. Se asume que el flujo es turbulento, isotrópico e incompresible. Diversos modelos de turbulencia RANS son contrastados y se emplean mallas estructuradas rectanuglares para discretizar el dominio analizado. La presencia de dos fluidos es modelada utilizando diferentes enfoques VOF y las simulaciones son ejecutadas empleando el algoritmo PIMPLE. El modelo es implementado mediante la plataforma de código abierto OpenFOAM y su respuesta es comparada con la del modelo comercial FLOW-3D. El análisis se lleva a cabo sobre dos partes diferentes de una estructura hidráulica, a saber, el aliviadero y el cuenco amortiguador, de forma separada. Además, un caso de aplicación práctica, donde el modelo reproduce el flujo en una estructura real, es presentado también a fin de probar la adecuación del modelo a casos de diseño aplicado. Se comprueban la independencia de la malla y la validación con datos experimentales de los resultados de todos los casos de estudio. La sensibilidad del modelo presentado a ciertos parámetros es analizada de forma exhaustiva empleando diferentes variables indicadoras. Los pros y contras de cada uno de éstos son planteados. Los modelos de turbulencia analizados son el Standard k-epsilon, el Realizable k-epsilon, el RNG k-epsilon y el SST k-omega. Los esquemas de discretización estudiados son: un método de primer orden upwind, uno de Van Leer de segundo orden y un esquema de segundo orden limitado de diferencias centradas. Los enfoques VOF analizados son el Partial VOF, implementado en OpenFOAM, y el TruVOF, implementado en FLOW-3D. En la mayoría de casos, el modelo k-epsilon aporta las estimaciones más precisas de perfiles de lámina libre de agua, pese a que el resto de variables, con alguna excepción, son mejor predichas por el RNG k-epsilon. Este modelo generalmente requiere mayores tiempos de cálculo. El k-omega reproduce correctamente los fenómenos bajo estudio, pese a que su precisión es generalmente más baja que la de los modelos k-epsilon. En lo que respecta a la comparación entre enfoques VOF y códigos, es imposible determinar cuál es el mejor. Por ejemplo, OpenFOAM, empleando el Partial VOF, logra reproducir la estructura interna del resalto hidráulico y todas las variables derivadas mejor que FLOW-3D, empleando el TruVOF, a pesar de que este último parece capturar mejor la transferencia de cantidad de movimiento y, por tanto, todas las variables derivadas. En el caso del flujo en aliviaderos escalonados, OpenFOAM captura mejor los perfiles de velocidad, pese a que FLOW-3D es más preciso en la estimación de los perfiles de lámina libre de agua. Conviene recalcar que ni tan sólo su respuesta a ciertos parámetros del modelo es comparable. Por ejemplo, FLOW-3D es significativamente menos sensible al refinado de malla que OpenFOAM. A la luz de la precisión de los resultados obtenidos en todos los casos, el modelo propuesto es completamente aplicable a casos de diseño más complejos, donde cuencos amortiguadores, aliviaderos escalonados y estructuras hidráulicas en general han de ser investigadas. / Les noves disposicions legals derivades del canvi climàtic dictaminen que cal que les estructures hidràuliques siguen capaces de funcionar correctament amb esdeveniments d'inundació associats a períodes de retorn de fins a 10,000 anys. Això, òbviament, implica adaptar la infraestrctura existent per satisfer aquests requeriments. A fi d'evitar riscs en la restitució dels cabals vessats al riu, com desbordaments o processos erosius i de socavació, el disseny hidràulic ha de recolzar-se en ferramentes fiables capaces de reproduir el comportament de les estructures hidràuliques. En aquest treball, es prsenta un model numèric CFD completament tridimensional per a reproduir el comportament de diferents tipus de flux aire-aigua en estructures hidràuliques. S'assumeix que el flux és turbulent, isotròpic i incompressible. Diferents models de turbulència RANS són contrastats i s'empren malles estructurades rectangulars per discretitzar el domini analitzat. La presència de dos fluids és modelada utilitzant diferents enfocaments VOF i les simulacions són executades emprant l'algorisme PIMPLE. El model és implementat mitjançant la plataforma de codi obert OpenFOAM i la seua resposta és comparada amb la del codi comercial FLOW-3D. L'anàlisi es du a terme sobre les diferents parts d'una estructura hidràulica, a saber, sobreeixidors esgraonats i vas esmorteïdor, de forma separada. A més, un cas d'aplicació pràctica, on el model reprodueix el flux a una estructura real, és presentat també a fi de provar l'adequació del model a casos de disseny aplicat. Es comproven la independència de la malla i la validació amb dades experimentals dels resultats de tots els casos d'estudi. La sensibilitat del model presentat a certs paràmetres és analitzada de forma exhaustiva emprant diferents variables indicadores. Els pros i contres de cadascun d'aquests són plantejats. Els models de turbulència analitzats són l'Standard k-epsilon, el Realizable k-epsilon, el RNG k-epsilon i l'SST k-omega. Els esquemes de discretització estudiats són: un mètode de primer ordre upwind, un de Van Leer de segon ordre i un esquema de segon ordre limitat de diferències centrades. Els enfocaments VOF analitzats són el Partial VOF, implementat en OpenFOAM, i el TruVOF, implementat en FLOW-3D. En la majoria de casos, el model Standard k-epsilon aporta les estimacions més precises de perfils de làmina lliure d'aigua, tot i que la resta de variables, amb alguna excepció, són millor predites pel RNG k-epsilon. Aquest model generalment requereix majors temps de càlcul. El k-omega reprodueix correctament els fenòmens sota estudi, tot i que la seua precisió és generalment més baixa que la dels models k-epsilon. Pel que fa la comparació entre enfocaments VOF i codis, és impossible determinar quin és el millor. Per exemple, OpenFOAM, emprant el Partial VOF, aconsegueix reproduir l'estructura interna del ressalt hidràulic i totes les variables derivades millor que FLOW-3D, emprant el TruVOF, tot i que aquest últim pareix capturar millor la transferència de quantitat de moviment i, per tant, totes les variables derivades. En el cas del flux en sobreeixidors esgraonats, OpenFOAM captura millor els perfils de velocitat, tot i que FLOW-3D és més precís en estimar els perfils de làmina lliure d'aigua. Cal deixar palès que ni tan sols la seua resposta a certs paràmetres del model és comparable. Per exemple, FLOW-3D és significativament menys sensible al refinament de malla que OpenFOAM. En base a la precisió dels resultats obtinguts en tots els casos, el model proposat és completament aplicable a casos de disseny més complexos, on vassos esmorteïdors, sobreeixidors esgraonats i estructures hidràuliques en general han de ser investigades. / Bayón Barrachina, A. (2017). Numerical analysis of air-water flows in hydraulic structures using computational fluid dynamics (CFD) [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90440 / Compendio