Embora o ressalto hidráulico seja um assunto já muito estudado, é igualmente um assunto de grande interesse, acerca do qual ainda existem diversos questionamentos a respeito de suas características. Por essa razão, buscou-se neste projeto o desenvolvimento de estudos experimentais e a proposição de um modelo teórico. Os trabalhos experimentais foram desenvolvidos com o uso de um sensor ultrassônico, para aquisição de dados instantâneos da superfície livre, sendo estudados ressaltos com número de Froude na seção supercrítica entre 1,94 e 5,26 e duas condições de controle a montante: comporta plana e vertedor de soleira espessa. As seguintes variáveis foram avaliadas a partir dos experimentos: comprimento do rolo, comprimento do ressalto, intensidade turbulenta vertical, perfil da superfície livre e frequências dos sinais de saída do sensor. Os perfis da superfície livre, considerando-se separadamente os dados de comporta e vertedor, foram ajustados a partir de uma equação heurística e as frequências características foram comparadas com os comprimentos característicos do ressalto. Além disso, foram efetuados registros fotográficos do escoamento com uma câmera de alta velocidade e luz laser para uma condição experimental (com baixo número de Froude supercrítico), sendo a superfície livre detectada por meio de técnicas usuais de processamento de imagens. O perfil médio obtido com o sensor foi semelhante ao perfil das imagens. Em relação ao modelo teórico proposto, este foi desenvolvido a partir de dois volumes de controle (VC) fixos, sendo obtidas duas equações para a relação entre o comprimento do rolo e a altura supercrítica. Verificou-se uma variação de quarenta porcento entre os valores previstos com as equações e os dados experimentais, em função da própria divergência dos dados de comprimento do rolo indicados pelos autores. De forma geral, o estudo mostrou-se relevante por possibilitar a avaliação da estrutura externa do ressalto hidráulico por meio de diferentes abordagens metodológicas. / Althought hydraulic jump has been studied for a long time, it is equally a theme of large interest, which many aspects related to its characteristics remain unanswered. Therefore, the development of experimental studies and the proposal of a theoretical model was sought in this project. The experimental works were carried out using an ultrassonic sensor, in order to acquire instantaneous data of the free surface, being studied hydraulic jumps with inflow Froude number ranging between 1.94 and 5.26 and two upstream control structures: plane gate and broad-crested weir. The following variables were evaluated: roller length, hydraulic jump length, vertical turbulent intensity, free surface profile, frequencies of the output data sensor. The free surface profiles, considering individually the plane gate and broad-crested weir, were adjested using a heuristic equation and characteristic frequencies were compared to the characteristic jump lengths. Furthermore, the flow was photographed using a high speed camera and a laser light for one experimental condition (for low inflow Froude number). The free surface in images were detected trought usual image processing techniques. The mean profile obtained from the sensor was very similar to the images profile. Regarding the theoretical model, it was developed considering two fixed control volumes (VC), obtaining two equations for the roller length and supercritical depth ratio. A variation of forty percent was observed between the predicted and experimental values, due to the own divergence among the roller length data suggested by the authors. Overall, the study was relevant, because it allowed the evaluation of the external structure of hydraulic jumps by means of different methodological approaches.

Je reporte ici une étude expérimentale sur la réorganisation inertielle de liquide dans un microcanal, constitutif des mousses liquides, appelé le bord de Plateau qui est soutenu par trois films de savon. Deux perturbations sont appliquées sur un bord de Plateau. Premièrement, une goutte y est ajoutée. La viscosité du liquide et taille initiale du bord de Plateau et de la goutte sont variés. La redistribution du liquide ajouté est pilotée par les forces capillaires. On observe un régime inertiel où un ressaut hydraulique capillaire se déplace à vitesse et géométrie constantes dans le bord de Plateau. Ce régime est décrit théoriquement et révèle le rôle majeur joué par les films de savon. On observe aussi un régime dominé par les effets visqueux où le liquide ajouté est redistribué selon une dynamique de type diffusive. La transition entre les deux régimes dépend des paramètres de contrôle du système et est caractérisée. La seconde perturbation est acoustique. Une plaque vibrante perturbe le bord de Plateau et les films. La taille du bord de Plateau, la fréquence et l’amplitude de forçage sont variées. Une onde de flexion se propage dans les films qui ont le bord de Plateau pour condition limite fixe ou libre selon sa masse. A haute amplitude, un régime non linéaire apparaît et le liquide dans le bord de Plateau se réorganise en trois zones de taille et d’amplitude d’oscillation très contrastées. Dans chacune des zones, le déphasage entre l’onde dans le film et l’onde dans le bord de Plateau est différent. Le système couplé du film et du bord de Plateau est modélisé par un oscillateur forcé dont la fréquence propre dépend de la fréquence de forçage. / I report an experimental study of inertial liquid reorganization into a liquid foam microchannel, also called a Plateau border supported by three soap films. Two perturbations are applied on the Plateau border. Firstly, a liquid drop is injected. Liquid viscosity, drop size and Plateau border size are changed. The liquid redistribution is drived by capillary forces. We observe an inertial regime where a capillary hydraulic jump move on the Plateau border with a constant shape and a constant velocity. This regime is modeled and shows the importance of soap films. We also observe a viscous-dominated regime where the added liquid is redistributed with a diffusive-like dynamic. The transition between the two regimes is investigated and qualitatively accounted for. Secondly, the Plateau border and the three films are vibrated by a plate. A bending wave is shown to propagate in the soap films with the Plateau border for free or fixed limit conditions according to its mass. For high amplitudes, a non linear regime appears and the liquid inside the Plateau border is redistributed along three zones of very contrasted size and oscillation amplitudes. In each zone, the phase difference between the wave in soap films and the wave in Plateau border is different. The system composed of films and the Plateau border is modelled by a forced oscillator with a resonance frequency which depends on the forced frequency.

The diploma thesis is focused on the evaluation of the suppression of supercritical current energy in the area of the river bed extension. The hydraulic model was used to simulate current conditions for different variants of river bed arrangement. Individual variants were then evaluated according to the relevant criteria and compared with each other. Results can be applied in hydrotechnical practice based on model similarity.

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.

No description available.

La chronologie des recherches théoriques et numériques exposées dans cet ouvrage est étroitement liée à notre attachement à lexpérimental et aux préoccupations pratiques des grands projets de constructions hydrauliques. Les applications variées qui sont envisagées quotidiennement au HACH (Hydrodynamique Appliquée et Constructions Hydrauliques Secteur Mécanique des Solides, des Fluides et des Structures - Département ArGEnCo Université de Liège), dont plusieurs exemples sont présentés, ont permis didentifier aussi bien des pistes damélioration des modèles numériques existants au sein de la suite WOLF(suite logicielle intégrée développée par le HACH pour la modélisation et loptimisation des écoulements à surface libre), que des besoins en nouvelles potentialités de représentation. Cest de là que sont nés la plupart des développements détaillés ici, avec comme objectif principal laugmentation des capacités des logiciels du HACH pour laide à la gestion et au design douvrages hydrauliques. Le dimensionnement de structures hydrauliques, tout comme la majeure partie des problèmes touchant à lhydrodynamique des écoulements à surface libre rencontrés dans la pratique, nécessite des études à grande et petite échelles, à laide de modèles adaptés localement aux phénomènes représentés, et donc variables au sein dune même étude selon le point particulier examiné. Dautre part, loptimisation de la forme ou du fonctionnement douvrages hydrauliques requiert des outils de calibration robustes permettant une approche objective. Ces derniers doivent de plus être couplés à des logiciels de simulation dont la représentativité et les temps de calcul sont en accord avec les exigences de loptimisation. Ces deux constats principaux posent le cadre des recherches entreprises et sont à la base de la définition des objectifs du travail. Les premiers chapitres de développements sattachent à décrire le cadre numérique de la suite logicielle WOLF, et plus particulièrement des codes 1D et 2D. La rationalisation des temps de calcul des simulations filaires à grande échelle est améliorée à ce stade par limplémentation au sein du logiciel unidimensionnel dun schéma dintégration temporelle implicite, en parallèle du schéma explicite existant. De même, certaines améliorations sont déjà apportées au logiciel WOLF2D. Elles concernent lextension automatique du domaine de calcul en fonction des mailles immergées émergées, le traitement des termes sources de pente de fond et de frottement en accord avec une approche énergétique, la conservation volumique du modèle ainsi que la réorganisation de la filière de résolution des équations de façon à permettre une totale latitude dans le choix du modèle de calcul utilisé. Lenrichissement des potentialités de modélisation des outils de la suite WOLF est ensuite poursuivi par létablissement, limplémentation et lapplication à des cas théoriques et pratiques, dun modèle de turbulence adapté aux caractéristiques spécifiques de la simulation des écoulements intégrée sur la hauteur deau. Afin de dépasser les limitations, tant informatiques que de discrétisation, inhérentes à lutilisation dune taille de maille unique sur un domaine de simulation bidimensionnel, des développements sont entrepris pour permettre de mener les calculs bidimensionnels sur un maillage structuré cartésien constitué de plusieurs zones à la taille de maille différente. Dans le même ordre didée, des développements sont réalisés pour permettre lutilisation de lensemble des outils de modélisation disponibles au sein du logiciel WOLF2D de façon simultanée et automatique au sein dune même simulation. Létape ultime de ces développements est réalisée en couplant les modèles uni- et bidimensionnel au sein dune simulation unique. Une fois toutes ces étapes de développement des modèles hydrodynamiques franchies, un logiciel adapté de calage automatique de paramètres est mis au point. Utilisable avec nimporte quel code de la suite WOLF, il permet la calibration de lensemble des paramètres physiques présents au sein des logiciels hydrodynamiques, ainsi que la résolution de tout problème doptimisation ou de calibration à laide des mêmes modèles. La parallélisation de ce logiciel basé sur la méthode des Algorithmes Génétiques ouvre la porte à des applications denvergure, dont le dimensionnement hydraulique douvrages sur base de simulations bidimensionnelles découlements turbulents à surface libre sur maillage multibloc. A chaque étape, la validation des développements est réalisée de façon rigoureuse par la confrontation des résultats numériques à ceux de cas test, théoriques et expérimentaux, originaux ou proposés dans la littérature. De nombreux exemples dapplications pratiques illustrent l'ensemble des potentialités de modélisation développées et prouvent leur applicabilité et leur efficacité face aux problèmes pratiques rencontrés par les ingénieurs hydrauliciens./ The chronology of the theoretical and numerical researches outlined in this text is closely linked to our attachment to the physical modelling and to the practical concerns related to important hydraulic projects. The various applications carried out daily in the HACH (Applied Hydrodynamics and Hydraulic Constructions - Solid, Fluid and Structures Mechanics ArGEnCo Department University of Liege), several of the being presented here, enabled to identify the ways to improve the existing numerical models of WOLF (integrated software package developed by the HACH for free surface flows modelling), as well as needs in new representation potentialities. The most of the developments described in this text were born from there, with as main objective to increase the capacities of the HACHs models to help to the management and the design of hydraulic constructions. The hydraulic structures design, and the main part of the practical problems related to free surface flows hydrodynamics, requires both large and small scales studies, with reliable models locally suited to the represented phenomena, and thus variable in a single study depending on the particular point examined. On another hand, the shape and working optimization of hydraulic structures requires robust calibration tools allowing an objective approach. The latter have to be linked to simulation software with modelling capacities and computation times in agreement with the optimization requirements. Both these assessments specify the framework of the researches of this thesis and are at the roots of the definition of the objectives of this work. The first chapters of developments aim to describe the numerical framework of the WOLF package, and more particularly the 1D and 2D models. The rationalization of the computation times for large scale one-dimensional simulations is improved at this stage by implementing in the 1D solver an implicit time integration scheme in parallel to the existing explicit one. Similarly, some improvements have been brought to the solver WOLF2D. They concern the automatic extension of the computation domain regarding the wet and dry cells, the treatment of the slope and roughness source terms with an energetic approach, the water volume conservation as well as the reorganization of the equations resolution scheme in order to be totally free in the choice of the mathematical model to solve. The enrichment of the modelling potentialities of the WOLF software is then pursued by setting, implementing and applying an original turbulence model suited to the specific characteristics of the depth integrated flow modelling. In order to get over the computer and modelling limitations inherent in the use of a single mesh size to model a 2D domain, developments have been carried out to allow the realisation of two-dimensional computations on a structured Cartesian grid composed of several areas with different mesh sizes. In the same way, developments have been carried out to use the whole of the mathematical models available in WOLF2D simultaneously and automatically in a single simulation. The ultimate step of these developments consisted in linking the 1D and the 2D models in a single computation. Following all these steps of developments of hydrodynamic models, a suitable tool for parameters automatic calibration has been set up. Usable with any solver of the WOLF package, it allows the calibration of the whole of the physical parameters present in the hydrodynamic solvers, as well as the resolution of any calibration or optimization problem with these models. The final parallelisation of this Genetic Algorithms based tool opens the door to complex applications, such as the hydraulic design of structures on the basis of two-dimensional simulations of free surface turbulent flows on multiblock grid. At each step, the validation of the developments is rigorously performed through the comparison of the numerical results with those from test cases, theoretical or experimental, original or from the literature. Several practical applications examples illustrate the whole of the developed modelling potentialities and prove their applicability and efficiency facing the most of practical problems encountered by hydraulic engineers.

Cette thèse porte sur la résolution numérique du modèle multi-dimensionnel d'écoulement cisaillé en eau peu profonde. Dans le cas d'un mouvement unidimensionnel, ces équations coïncident avec les équations de la dynamique de gaz pour un choix particulier de l'équation d'état. Dans le cas multi-dimensionnel, le système est complètement différent du modèle de la dynamique de gaz. Il s'agit d'un système EDP hyperbolique 2D non-conservatif qui rappelle un modèle de turbulence barotrope. Le modèle comporte trois types d'ondes correspondant à la propagation des ondes de surface, des ondes de cisaillement et à celle de la discontinuité de contact. Nous présentons dans le cas 2D un schéma numérique basé sur une nouvelle approche de ``splitting" pour les systèmes d'équations non-conservatives. Chaque sous-système ne contient qu'une seule famille d'ondes: ondes de surface ou ondes de cisaillement, et discontinuité de contact. La précision d'une telle approche est testée sur des solutions exactes 2D décrivant l'écoulement lorsque la vitesse est linéaire par rapport aux variables spatiales, ainsi que sur des solutions décrivant des trains de rouleaux 1D. Finalement, nous modélisons un ressaut hydraulique circulaire formé dans un écoulement convergent radial d'eau. Les résultats numériques obtenus sont clairement similaires à ceux obtenus expérimentalement: oscillations du ressaut et son rotation avec formation du point singulier. L'ensemble des validations proposées dans ce manuscrit démontre les aptitudes du modèle et de la méthode numérique pour la résolution des problèmes complexes d'écoulements cisaillés en eau peu profonde multidimensionnels. / This thesis is devoted to the numerical modelling of multi-dimensional shear shallow water flows. In 1D case, the corresponding equations coincide with the equations describing non--isentropic gas flows with a special equation of state. However, in the multi-D case, the system differs significantly from the gas dynamics model. This is a 2D hyperbolic non-conservative system of equations which is reminiscent of a generic Reynolds averaged model of barotropic turbulent flows. The model has three families of characteristics corresponding to the propagation of surface waves, shear waves and average flow (contact characteristics). First, we show the ability of the one-dimensional conservative shear shallow water model to predict the formation of roll-waves from unstable initial data. The stability of roll waves is also studied.Second, we present in 2D case a new numerical scheme based on a splitting approach for non-conservative systems of equations. Each split subsystem contains only one family of waves (either surface or shear waves) and contact characteristics. The accuracy of such an approach is tested on exact 2D solutions describing the flow where the velocity is linear with respect to the space variables, and on the solutions describing 1D roll waves. Finally, we model a circular hydraulic jump formed in a convergent radial flow of water. Obtained numerical results are qualitatively similar to those observed experimentally: oscillation of the hydraulic jump and its rotation with formation of a singular point. These validations demonstrate the capability of the model and numerical method to solve challenging multi--dimensional problems of shear shallow water flows.

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.