Tesi sul tema "Direction de transport de sédiment"
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Baville, Paul. "Stratigraphic correlation uncertainty : On the impact of the sediment transport direction in computer-assisted multi-well correlation". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0111.
Subsurface modeling is a way to predict the structure and the connectivity of stratigraphic units by honoring subsurface observations. These observations are commonly be sampled along wells at a large and sparse horizontal scale (kilometer-scale) but at a fine vertical scale (meter-scale). There are two types of well data: (1) well logs, corresponding to quasi-continuous (regular sampling) geophysical measurements along the well path (e.g., gamma ray, sonic, neutron porosity), and (2) regions, corresponding to categorical reservoir properties and defined by their top and bottom depths along the well path (e.g., biozones, structural zones, sedimentary facies). Markers are interpreted along the well path and can be associated in order to generate a consistent set of marker associations called well correlations. These well correlations may be generated manually (deterministic approach) by experts, but this may be prone to biases and does not ensure reproducibility. Well correlations may also be generated automatically (deterministic or probabilistic approach) by computing with an algorithm a large number of consistent well correlations and by ranking these realizations according to their likelihood. The likelihood of these computer-assisted well correlations are directly linked to the principle of correlation used to associate markers. This work introduces two principles of correlation, which tend to reproduce the chronostratigraphy and the depositional processes at the parasequence scale: (1) "a marker (described by facies and distality taken at the center of an interval having a constant facies and a constant distality) cannot be associated with another marker described by a depositionally deeper facies at a more proximal position, or a depositionally shallower facies at a more distal position", and (2) "the lower the difference between a chronostratigraphic interpolation (in between markers) and a conceptual depositional profile, the higher the likelihood of the marker association". These two principles of correlation are first benchmarked with analytical solutions and applied on synthetic cases. They have then been used (1) to predict the connectivity of stratigraphic units from well data without strong knowledge on depositional environments by inferring the correlation parameters, or (2) to evaluate the likelihood of a hypothetical depositional environment by generating stochastic realizations and assessing the uncertainties. The methods are applied on a siliciclastic coastal deltaic system targeting a Middle Jurassic reservoir in the South Viking Graben in the North Sea.This work enables (1) to define two specific principles of correlation defined by a few parameters that can be used to generate stochastically well correlations within coastal deltaic systems, and (2) to open the path towards a simple combination of specific principles of correlation to obtain a better characterization of coastal deltaic systems by assessing the uncertainties
Tran, Thu Tam. "Modélisation numérique de l'interaction houle-courant-sédiment". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10210.
Nagel, Tim. "Étude numérique des interactions multi-échelles écoulement-sédiment-structure par une approche multiphasique". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI050/document.
The work undertaken in this PhD thesis was to develop and use numerical models to investigate the multi-scale interactions between an offshore wind turbine and the local ocean and sediment dynamics. First, the interactions between the coupled ocean-sediment system and the atmospheric wake generated by an offshore wind turbine are investigated using an idealized two-dimensional model developed during this Phd thesis and written in fortran. The model integrates the shallow water equations for the ocean together with the Exner equation for the sediment bed. In a second part, the 3D scour phenomenon around a vertical cylinder in a steady current is studied using a two-phase flow eulerian-eulerian solver, sedFoam, written within the framework of the numerical toolbox OpenFOAM. The two-phase flow approach accounts for small-scale processes by avoiding the traditional assumptions made for sediment transport modeling, such as a local corre- lation between the sediment flux and the fluid bed shear stress.Regarding the atmospheric wake generated by a turbine, the results shows that its impact on the ocean’s surface can generate vortices. The resulting turbulent ocean dynamics is controlled by the wake parameter S = CdD/H, where D is the wake diameter at the impact location on the ocean surface, Cd is the quadratic friction coefficient between the ocean and the sediment and H is the oceanic layer depth. A turbulence parameterization based on S is proposed, allowing for upscaling simulations in larger scales Reynolds Averaged Navier-Stokes (RANS) models. It is shown that the ocean dynamics has an effect on the available wind power. The results also show that the instantaneous sediment dynamics is strongly coupled with the ocean one but that the overall seabed elevation variations remain small (a few millimeters/month). The morphodynamic impact of the wake is thus negligible.Concerning the two-phase flow simulation of scour, sedFoam is first validated on 1D and 2D configurations. Then, 3D simulations around a vertical cylindrical pile are presented. At first, a validation of the Unsteady Reynolds Averaged Navier-Stokes (URANS) turbulence model developed in this work is performed on a configuration without sediment. The results show that the vortices structures responsible for scouring, the Horse Shoe Vortex (HSV) and the vortex-shedding in the lee of the cylinder are correctly reproduced. Then, 3D two-phase flow simulations of the scour around a cylindrical pile have been carried out in a live-bed configuration. This work is the first attempt to model 3D scour phenomenon using the two-phase flow approach. Such simulations represent a real challenge in terms of high performance computing. The good agreement between the numerical predictions and the literature experimental results provide the proof of concept that the two-phase flow approach can be used to study complex 3D and unsteady flow configurations. The relationship between the local bed shear stress, the sediment flux and the local sediment bed slope is further investigated. The deviation of the results from a uniform flow configuration is further analyzed to identify the relevant sediment transport mechanisms associated with the HSV, the slope in the scour mark and the vortex-shedding downstream of the cylinder. Finally, the numerical results show a grid sensitivity of the morphological predictions in the lee of the cylinder that are most probably related to small-scale resolved vortical structures. This highlights the need for two-phase flow Large Eddy Simulations on this configuration in the future
Wissocq, Aubéry. "Etude du transport réactif de Sr et Cs dans un sédiment gréso-argileux carbonaté du site de Cadarache". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLE027/document.
As part of the environmental monitoring of its installations under nominal operating conditions or in accident situation, CEA must ensure the implementation of operational methods and tools to measure, control and predict the discharge of its installations into the environment, atmosphere, soil and groundwater. This work is part of the implementation of a reactive transport tool, which allows predicting the migration of radionuclides in trace concentration such as 90Sr and 137Cs, the main radionuclides of interest, in soils and rocks. The aim of this thesis is to evaluate the applicability and predictive nature of a coupled chemistry-transport model in the case of migration of Cs and Sr in a natural sediment, representative of the aquifer underlying the nuclear site of Cadarache. The retention model used is based on the Multi-Site Ion Exchange Theory, integrated in PhreeqC coupled with HYDRUS 1D (HP1) or Crunchflow.The characterization of the physico-chemical properties of the sediment studied and the identification of the reactive minerals allow to develop a database of retention of Sr2+, Cs+ and Ca2+ (major cation of the medium) on the clay minerals mostly present, illite and smectite. The construction of this database was based on a critical review of the data in the literature, supplemented by the acquisition of missing data. From this database and assuming the additivity of the retention properties of pure minerals in a material considered as a mixture of pure minerals, it was possible to verify the applicability of the retention model in the case of the adsorption of Sr2+ and Cs+ on the sediment.Finally, this retention model could be coupled to a transport model and applied to the case of the migration of Sr and Cs in sediment columns. These experiments were carried out on two types of column, at the centimeter scale on standard columns and at a decimetric scale on an experimental device equipped with a X generator recording continuously the physicochemical parameters within the column. Simulations of the Sr reactive transport experiments by the multi-sites ion exchange model coupled with the advection-dispersion equation were able to adequately reproduce the Sr breakthrough curves without any parameter adjustments. The dispersivity coefficients of each column were determined in non-reactive transport experiments using inert tracers (2H, Cl- and I-). Moreover, the Cs breakthrough curves seem more difficult to reproduce, which could be due to the uncertainties still existing on the retention parameters related to this element or a kinetic effect.The good agreement between the results of the reactive Sr transport experiments in a column at two different scales and the simulations showed that the reactive transport model implemented allows reproducing the behavior of Sr in the Cadarache sediment without parameter adjustment by considering the chemical retention by an ion exchange process on the clay minerals of the system. This first step, essential to the evaluation of the model confirms the predictive nature of this model, insofar as physicochemical conditions are well constrained
Morgane, Houssais. "Étude expérimentale du transport en rivière par charriage d'un sédiment bimodal : vers un modèle général du transport à plusieurs tailles de grains". Phd thesis, Institut de physique du globe de paris - IPGP, 2013. http://tel.archives-ouvertes.fr/tel-00880876.
Houssais, Morgane. "Etude expérimentale du transport en rivière par charriage d'un sédiment bimodal : vers un modèle général du transport à plusieurs tailles de grains". Paris 7, 2013. http://www.theses.fr/2013PA077074.
Despite several decades of investigations, accounting for the effect of the wide range of grain sizes composing the bed of rivers on bedload transport remains a challenging problem. We investigate this problem by studying experimentally the influence of grain size distribution on bedload transport in the simple configuration of a bimodal sediment bed composed of a mixture of 2 populations of quartz grains of sizes Di = 0. 7 ± 0. 1 mm and D2 = 2. 2 ± 0. 4mm, respectively. The experiments are carried out in a tilted rectangular flume inside which the sediment bed is sheared by a steady and spatially uniform turbulent flow. Using a high-speed video imaging System, we focus on the measurement of the two bedload flux components : the average particle velocity and the number of moving particles per unit surface of the bed. These two quantifies are measured separately for each population of grains as a function of the dimensionless shear stress (or Shields number) and the fraction of the bed surface covered with small grains. We show that the average velocity and the surface density of moving particles obey the same equations as those reported by Charru [2006] for a bed of homogeneous grain size. Once in motion, the grains follow therefore similar laws whether the bed is made of uniform sediment or of a bimodal mixture. This suggests that the erosion deposition model established by Lajeunesse et al. [2010] for a bed of uniform sediment can be generalized to the case of a bimodal one. The only difference evidenced by our experiments concerns the critical Shields number for incipient sediment motion. Above a uniform sediment bed, the latter depends on the particle Reynolds number through the Shields curve [Shields, 1936]. In the case of a bimodal bed, our experiments show that the critical Shields numbers of both populations of grains decrease linearly with the fraction of the bed surface covered with small grains. We propose a simple model to account for this observation
Van, Do Lan Anh. "Modélisation du transport de sédiments mixtes sable-vase et application à la morphodynamique de l'estuaire de la Gironde (France)". Phd thesis, Université Paris-Est, 2012. http://pastel.archives-ouvertes.fr/pastel-00862365.
Nguyen, Duc Hau. "Interaction fluides-particules solides à l'interface eau-sédiment : Une approche de modélisation diphasique : Une approche de modélisation diphasique". Caen, 2011. http://www.theses.fr/2011CAEN2085.
This work is devoted to the study of fluid-particle interactions at the sediment-water interface by a two-phase flow modelling approach. The proper orthogonal decomposition (POD) is used to analyze numerical data. The developed approach differs from the classical one by resolving the mass and momentum equations and the transport equation for turbulent kinetic energy, separately for each phase. Transfer terms of momentum and turbulent kinetic energy between phases take into account fluid-particle interactions. Two problems in which an interface between the clear water and the very dense mixture (water and sediment) are considered: the dredged-sediment releases in the seawater and the instability at the interface between the clear water and the heavy suspension (mixture of water and sediment like mud) (Kelvin-Helmholtz instability). The two-phase flow modelling reproduces quantitatively the main processes involved in sediment transport of non-cohesive particles in very dense suspensions. Especially, the numerical results confirm the existence of a horizontal velocity lag between the fluid and particles. The flow within this structure is successfully captured by a few POD eigenfunctions
Bleau, Daniel Alexandre. "Transport de sédiments en rivière graveleuse affectée par des couverts de glace". Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/11093.
Raus, David. "Transport sédimentaire sur rugosités immobiles : de l'hydrodynamique locale à la morphodynamique". Phd thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/23587/1/Raus_David.pdf.
Van, Lan Anh. "Modélisation du transport de sédiments mixtes sable-vase et application à la morphodynamique de l'estuaire de la Gironde (France)". Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1165/document.
This study attempts to model sediment transport rates and the resulting bed evolution in a complex estuarine environment: the Gironde estuary, characterized by a high hetereogeneity in the sediment bed composition, with the presence of both cohesive and non-cohesive sediments and sand/mud mixtures. Our main objective is to extend an existing 2D morphodynamic model developped by Huybrechts et al (2012b) for non-cohesive sediments, to account for the presence of mud and to draw some preliminary step for a fully mixte sediment morphodynamic model. Our framework is the finite element Telemac system (release 6.1), where the two-dimensional (depth averaged) approach has been selected for large scale and medium term simulations.The first part of this work is devoted to the understanding of sedimentation-consolidation processes for pure mud, combining laboratory experiments and 1D vertical models. Cohesive processes are then integrated in the 2D (depth-averaged) large scale morphodynamic model of the Gironde estuary developed by Huybrechts et al. (2012b). Erosion/deposition experiments were performed at the RWTH laboratory (University of Aachen, Germany) to calibrate the erosion and deposition law parameters. Moreover, the effect of consolidation is taken into account through the implementation of a 1DV Gibson-based sedimentation-consolidation model (Thiebot et al., 2011) using analytical closure equations for permeability and effective stress. Special attention is paid to the initialisation of the bed structure. Comparisons between measurements and model results are achieved on both suspended sediment concentration records and on medium term (5-year) bed evolutions.In the second part, a new 1DV model for the hindered settling of sand-mud mixtures has been developed based on the background of non-cohesive bi-disperse models. The numerical solution has been constructed by considering a high-order of accuracy in space via a Weighted Essentially Non Oscillatory (WENO) reconstruction technique and in time via a local space-time Discontinuous Galerkin (DG).The model is then validated against a large range of experimental data (mono-disperse sand, mud, non-cohesive bi-disperse and non-cohesive/cohesive mixture)
Reichinger, Melanie [Verfasser]. "Investigations of the direction-driven water and ion transport along the interfaces and through polymer networks / Melanie Reichinger". Paderborn : Universitätsbibliothek, 2018. http://d-nb.info/1153824604/34.
Armstrong, Lawrence. "Étude de l'érosion des berges et du transport de sédiments d'une micro-rivière à chenal droit". Phd thesis, Université Paris-Diderot - Paris VII, 2003. http://tel.archives-ouvertes.fr/tel-00130323.
Antoine, Germain. "Dynamique des matériaux en suspension (MES) le long de rivières aménagées de montagne : exemple de l'Arc en Maurienne de l'Isère". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-01067695.
Durin, Bertrand. "Transfert et transport colloïdal de polluants métalliquesApplications en assainissement routier". Phd thesis, Université de Nantes, 2006. http://tel.archives-ouvertes.fr/tel-00104567.
van, Gaalen Joseph F. "Longshore Sediment Transport From Northern Maine To Tampa Bay, Florida: A Comparison Of Longshore Field Studies To Relative Potential Sediment Transport Rates Derived From Wave Information Study Hindcast Data". Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1280.
Lin, Husheng. "Le transport solide en collecteur unitaire d'assainissement et sa modélisation". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1993. http://tel.archives-ouvertes.fr/tel-00520688.
Zhang, Jiong. "Experimental and Numerical Investigations of Flow and Solid Transport in Urban Area". Phd thesis, INSA de Rennes, 2012. http://tel.archives-ouvertes.fr/tel-00764519.
Carbonari, Costanza. "Processus de tri granulométrique dans le transport par charriage : une étude théorique et expérimentale pour les rivières à gravier". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU009/document.
Field and laboratory investigations indicate that gravel bed rivers with poorly-sorted grain size distribution and low lateral confinement, such as in the case of multi-thread, braided and transitional rivers but also wandering single-thread rivers, can simultaneously present active channel variations, both in the planimetric and altimetric directions, together with planimetric and vertical sorting.Actually channel adjustments present a complex interaction with sorting processes. transport and depositional processes of heterogeneous sediment mixtures induce the formation of various sorting patterns, among which free migrating patches such as sorting waves also known as bedload sheets. Such sorting waves are mainly observed by the alternation of bands of finer and coarser material in the streamwise direction.This PhD research investigates the sorting processes of a bimodal grain size distribution both in the lateral and in the vertical direction, with particular focus on the study of bedload sheets.The main aim of this work is to investigate the effects of lateral confinement on river bed morphodynamics and in particular on grain sorting processes; and besides, given that grain sorting plays a crucial role in affecting longitudinal river profile, as well as sediment patterns and bed forms, being indeed the connection between bed topography and bed sediment composition close, we would like to provide simple theoretical analyses and tools able to predict morphodynamic bed river variations driven by sortingDifferent methodologies are applied to successfully achieve this purpose.Firstly, a deep investigation of the state of knowledge of mixed-size sediment morphodynamics, sorting processes, sorted sediment patterns and bedload sheets is carried out.Then, a 1D linear stability analysis of a uniform flow above an erodible bed composed by a bimodal mixture of sediments is performed and investigation of the associated eigenvectors, amplitude of perturbations and migrations rate is discussed. Results are presented in terms of arising instabilities dominated by sorting. Although the monodimensional shallow-water framework, the simple flow model adopted allows for the formulation of an algebraic eigenvalue problem that can be solved analytically, allowing for a deep insight into the mechanisms that drive instabilities.Then, small scale flume experiments are carried out by reproducing three different flow confinement configurations and involving a bimodal mixture of natural sediments. All the configurations show large fluctuations of parameters characterising bed system in terms of bed sediment composition, slope, active channel width and sediment transport rate. The analysis of such parameters allows defining feedbacks among morphological variables. Results of such investigations shed light on the role of lateral confinement on sorting processes and morphodynamics of barebed rivers
Kroll-Rabotin, Jean-Sébastien. "Analyse physique et modélisation de la séparation centrifuge de particules ultrafines en film fluant : application au séparateur industriel Falcon". Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0077/document.
Enhanced gravity separators are widely used in minerals beneficiation, as their superior gravity field enables them to separate particles within narrow classes of density and size. This study aims to shed light on the Falcon concentrator’s ability to separate particles with size and density ranges lower than usual, 1 to 100 micrometers and 1.2 to 3.0 s.g. respectively. Differential particle settling being identified as the prevailing separation mechanism under such conditions, this study couples a theoretical and numerical approach with targeted experiments to build a predictive Falcon separation model that embeds phenomenological fluid and particle flow analysis. Based on this model, physical limitations were identified and quantified through explicit relations between operating parameters, and particle size and density ranges. Falcon’s efficiency to beneficiate dredged sediments was characterized in this way
Theule, Joshua. "Etude géomorphologique de la dynamique sédimentaire de torrents à lave (Alpes Françaises)". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00864986.
Chauchat, Julien. "Contribution à la modélisation diphasique du transport sédimentaire en milieux côtiers et estuariens". Phd thesis, Université de Caen, 2007. http://tel.archives-ouvertes.fr/tel-00173387.
En terme de résultats, nous montrons que l'approche développée est capable de reproduire quantitativement les principaux processus mis en jeu dans le transport sédimentaire de particules non cohésives : la sédimentation et la dispersion turbulente des particules en milieu dilué. Le modèle développé confirme l'existence d'une différence de vitesse horizontale entre les particules et l'eau. Il simule les effets de dispersion des particules par le mouvement turbulent du fluide et l'atténuation de l'énergie cinétique turbulente du fluide due à la présence des particules. Une autre originalité de ce travail est de proposer un modèle diphasique à surface libre, bidimensionnel vertical, pour la simulation du transport sédimentaire. Nous avons identifié des lacunes entre les théories et les expériences notamment pour la simulation de la turbulence en écoulement dense. Nous proposons des solutions pour améliorer la simulation du comportement de matériaux cohésifs. Une tentative de simulation hydrosédimentaire sur l'estuaire de la Seine est présentée. Le phénomène de bouchon vaseux est qualitativement reproduit par le modèle sans qu'aucune loi d'érosion ou de dépôt ne soit imposée.
Delmotte, Sébastien. "Rôle de la bioturbation dans le fonctionnement biogéochimique de l'interface eau-sédiment : modélisation de la diversité des transports biologiques et effets sur la diagenèse précoce des sédiments d'une retenue". Toulouse 3, 2007. http://www.theses.fr/2007TOU30122.
This study deals with the role of bioturbation in the early diagenesis of freshwater sediments, particularly the effects of the diversity of the biological transports. To understand the complex interactions between the bio-transports and the reactions of matter transformation, some models of reactive transport were developed including the bio-transport diversity. In a first chapter, cadmium transport by oligochætes tubificids was modelled using an existing dataset. Then, the more complex case of the organic matter mineralization in the Malause reservoir (West South of France) has been addressed. Bioturbation by the natural benthic community was measured. A model of early diagenesis of organic matter was developed including this bioturbation, and particularly the non-local transports. Finally, an extension of bioturbation models is proposed in the last chapter, to account for the effects of the patchiness in the distribution of bioturbators
Cordier, Florian. "Morphodynamique des bancs dans des rivières aménagées à granulométrie étendue". Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1149/document.
Rivers often present a wavy bed topography due to the presence of bars, corresponding to large sediment deposits alternating with deeper areas (pools). Intense and continual river engineering works altering the river geometry, flow regime and sediment supply can impact bar morphodynamics at the reach scale. A deep knowledge of bar processes is important for river managers, because bars actively control the river bed topography and influence bank erosion, with consequences for navigation, water intakes, infrastructure and the quality of their habitats. Although the origin of bar formation and propagation is well understood, the understanding of bar morphodynamics in rivers remains limited due to the non-linearity of combined natural and anthropogenic effects. Sediment non-uniformity is an inherent characteristic of rivers, but its impact on bar properties, even considering simple configurations, is still unclear. This Ph.D. thesis aims at investigating the impact of sediment size heterogeneity on bars in rivers with non-erodible banks, using a two-dimensional morphodynamic model implemented in the Telemac-Mascaret system. The necessary model developments are brought to comply with the state of the art on the modelling of heterogeneous sediment with bars. Then, the model is used to study bar morphodynamics in a straight channel on the basis of laboratory experiments. Eventually, the analysis is transferred in a 1 km reach of the Loire river characterized by a relatively complex geometry. General outcomes validate the modelling approach and demonstrate the application portability for other study cases, shed more light on the relationship between non-uniform sediment and bars, and can be later used as recommendations for river managers
Cartier, Adrien. "Évaluation des flux sédimentaires sur le littoral du Nord-Pas de Calais : vers une meilleure compréhension de la morphodynamique des plages macrotidales". Phd thesis, Université du Littoral Côte d'Opale, 2011. http://tel.archives-ouvertes.fr/tel-00821126.
Die, Moran Andrés. "Physical and numerical modelling investigation of induced bank erosion as a sediment transport restoration strategy for trained rivers : the case of the Old Rhine (France)". Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1125.
Sediment transport dynamics, often heavily modified by river training, are not yet sufficiently considered as a significant factor in riparian environmental quality and river restoration strategies. Approaches for restoring a river's sediment in quantity and in grain size distribution, so that it is compatible with both ecological and human needs, are still under development. Furthermore, existing approaches such as direct sediment injection are often expensive and require human intervention. This thesis explores induced bank erosion, a more environmentally sustainable alternative. This approach involves increasing the potential for erosion at certain sites along the bank of a trained river, and allowing them to be eroded during high flow periods. Two modelling approaches, physical scaled models and numerical simulation, were used to study a site located on the Old Rhine downstream of Basle (Switzerland) where existing bank protection groynes will be modified to induce bank erosion. Firstly, different modification options were tested over a range of flow rates with a Froude-scaled undistorted movable-bed physical model. The physical model used a mixture of four grain sizes to reproduce the bank grain size distribution found at the site, and was scaled according to a specific method which accurately represents initiation of motion for each grain size. An effective bank erosion strategy was found that releases sediment without compromising the safety of an adjacent navigation channel through excessive bank retreat. Subsequently, the capability of the Telemac2D two-dimensional depth-averaged numerical modelling system to model bank erosion and failure processes was assessed, and the existing bank failure algorithm was modified in order to improve results. Algorithm developments were tested with two laboratory test cases. Then, the physical model tests were simulated at their same scale. Simulations reproduced the processes present in the physical model tests, and volumes of eroded and deposited sediment were of the same order of magnitude
Lepage, Hugo. "Traçage de la dispersion des sédiments contaminés dans les bassins versants côtiers de Fukushima". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112183/document.
Large quantities of radionuclides were released into the atmosphere by the Fukushima Dai-Ichi Nuclear Power Plant (FDNPP) after the earthquake-triggered tsunami devastated the eastern coast of Japan on March 11, 2011. Many of these radionuclides (20%) were deposited on soils of the Fukushima Prefecture. This PhD thesis develops original fingerprinting methods to track the dispersion of contaminated particles following this accident. The study focuses on 3 coastal catchments north of the FDNPP (Mano — 175km², Niida — 270km² and Ota — 75km²) draining heavily contaminated areas of the radioactive plume. The Fukushima Prefecture is characterized by an erosive climate, with the occurrence of spring floods and summer typhoons. To study the dispersion of the radioactive contamination, soil samples and sediment drape deposits were collected during 6 sampling campaigns (every six months between November 2011 and May 2014; i.e., after the major flood events). Each sample was analyzed by gamma spectrometry to determine radionuclide activities, and several soil and sediment samples were also analyzed by neutron activation analysis to determine their geochemistry. First, the analysis of 137Cs activity in 10 soil cores collected in paddy fields confirmed the limited migration of radiocesium with depth in the soils of the coastal catchments. More than 90% of the contamination was still concentrated in the uppermost 2cm of the soils by November 2013. Particles contaminated were therefore available for mobilization and transport downstream by processes that govern soil erosion. Second, metastable silver-110 (110mAg) was detected in most of the samples collected between November 2011 and November 2012, and our investigation showed that this radionuclide has a similar behavior as 137Cs in soil and sediment. Consequently, we used 110mAg to track the dispersion of the contamination as the 110mAg/137Cs activity ratio in soils of the Niida catchment showed significant differences between upstream and downstream locations. The use of a binary mixing model allowed the identification of a seasonal cycle of erosion and dispersion of particles. However, as 110mAg has a short half-life (250 days), it rapidly decayed and could not be detected anymore by May 2013. To overcome its disappearance, the contribution of soils located on the mountainous plateaus to the sediment transiting the river in the coastal plains was quantified based on their 137Cs signature. Binary mixing models were used, based on the distributions of 137Cs in mountainous areas (> 20 kBq/m²) and in coastal plains (< 20 kBq/m²). The results demonstrated that the contribution of the mountainous area varied in the different catchments. In the Niida catchment where no dam has been built, the mountainous area supplies more sediment to the river (≈46%) than in the Mano catchment that has a dam (≈20%). These results show the impact of dams generating a sediment disconnectivity. Finally, the soil map of the region was used in order to identify the soil types that may supply sediment to the rivers. The main soil types (Andosols, Cambisols and Fluvisols) were characterized by their geochemical composition, and Sc and Yb were identified as the most discriminant elements. The distributions of these elements in the three sources were used in a mixing model. Results show that Fluvisols are the main source supplying >70% of sediment to the rivers in both catchments. This soil type is mainly found in paddy fields, which confirms the enhanced erodibility of these cultivated areas. In the future, the dataset compiled could be used to improve soil erosion model operating at the catchment scale. Moreover, the impact of the ongoing decontamination works on the dispersion of contaminated sediments should be investigated
Bouteloup, Joris. "Simulation numérique de la dynamique d'un lit granulaire cisaillé par un fluide visqueux". Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/17966/1/Bouteloup_Joris_INPT.pdf.
Dutra, Maia Poliana. "Le rôle des échanges entre le fleuve Amazone et la plaine d'inondation dans les processus de transport, de spéciation et de piégeage du mercure". Toulouse 3, 2008. http://www.theses.fr/2008TOU30266.
One of the major environmental problem in the Amazon basin is the risk of mercury (Hg) contamination in aquatic environments and in riparian populations. The organic form of this element, the monomethylmercury (MMHg), shows a high toxicity and can reach elevated levels in fish due to the bioaccumulation and biomagnification processes in the food web. High rate of Hg methylation were measured particularly in floodplain lakes and in dam reservoirs. Even if in the Amazon basin floodplains occupy ~5% of the watershed area, they are still poorly studied. In the present work, we study the role of the water exchanges between the Amazon River and the floodplain lakes in the transfer, transport, partition and storage of mercury. Our study area is the "várzea do Curuai ", located along the Amazon River, 900 km upstream from the mouth. Most of the studied floodplain lakes, in particular all the white water lakes, receives water and sediment from the mainstream, whereas the black water lakes are more influenced by runoff and groundwater inputs. This work shows that the cycle and the distribution of the Hg species in the "várzea do Curuai " are more controlled by the hydrological dynamics of the Amazon R. And the local watershed. In the floodplain lakes, the MMHg and total Hg are mainly transported in the particulate phase, especially during the rising water stage when the river is flooding the lakes. During the water and sediment transfer in floodplain lakes, different Hg speciation processes occur, such as: i) the coagulation or flocculation of inorganic mercury with organo-mineral complexes that limits the amount of mercury available for bacterial methylation; effectively, we don't observe any MMHg enrichment between the Amazon River and the white water lakes, ii) a probably photo-reduction of Hg2+ in Hg° and its volatilisation in the atmosphere, inducing a depletion of dissolved Hg in the surface waters, iii) the re-suspension process of bottom sediments by the wind action and by bioturbation, enriching the water column in particulate Hg associated with oxy-hydroxides of Fe and Mn, iv) the Hg methylation and desorption of particulate MMHg but only in the black water lakes that are characterized by the reductive conditions. .
Villeneuve, Jean-Pierre. "Géochimie des composés organochlores dans l'environnement marin". Paris 6, 1986. http://www.theses.fr/1986PA066153.
Martin, Laurent. "Fonctionnement écologique de la Seine à l'aval de la station d'épuration d'Achères: données expérimentales et modélisation bidimensionnelle". Phd thesis, École Nationale Supérieure des Mines de Paris, 2001. http://pastel.archives-ouvertes.fr/pastel-00005463.
Puhl, Patricia Roberta. "O campo de dunas transgressivo da barreira costeira holocênica no litoral norte do Rio Grande do Sul: possíveis controles do seu desenvolvimento". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/164334.
In the north coast of Rio Grande do Sul, to the north of Xangri-lá beach, the Holocene barrier is partially covered by the modern and relatively active phase of a transgressive dune field, while to the south of this balneario the dune field completely covers the barrier. This work contributed to the knowledge about this differentiated development behavior of the modern phase of the transgressive dune field on the holocene barrier. Time series of wind (direction and speed) and precipitation of meteorological stations located to the south and north of Xangri-lá were used, as well as simultaneous wind measurements using portable anemometers, immediately to the north and south of this balneario. Sand transport potentials were calculated for both meteorological stations. Historical records of the Tramandaí station (further south) indicated higher wind speeds and lower precipitation relative to the Torres station (further north). Due to the greater speed of the winds in Tramandaí, the potential of sand transport in this locality was higher than Torres, indicating the favor of the migration of the dunes in its proximities. The uneven developmental behavior of the modern phase of the transgressive dune field can then be related to the higher speed and frequency of the NNE, NE, ENE and E winds in Tramandaí (ie, south of Xangri-lá), as well as the lower precipitation also favors more efficient sand transportation south of Xangri-lá.
Nord, Guillaume. "Modélisation à base physique des processus de l'érosion hydrique à l'échelle de la parcelle". Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00111955.
Foucher, Anthony. "Reconstitution de la cascade sédimentaire en contexte de plaine agricole drainée : sources, voies de transfert et stockage de matière dans le bassin versant du Louroux (Indre et Loire)". Thesis, Tours, 2015. http://www.theses.fr/2015TOUR4031/document.
Soil erosion is identified as one of the main factors influencing the physico-chemical degradation of the aquatic environments. This phenomenon has been largely described on contrasted topographic areas but there is a gap of knowledge about sediment mobilization/transfer in lowland areas despite the high connectivity level between the potential sources of sediment and the water bodies. In this context we have implemented an integrated multi-parameter approach allowing to track the sediment dynamics in a drained lowland area (the Louroux pond catchment: 47.16°N – 0.78°E) by starting from the sources of sediment to their accumulation in a sedimentary receptacle: the middle-age Louroux pond. The aims of this study are (i) to quantify at long (approx. 60 years) and short time scales (<10 years) the evolution of the erosion rate in the hillslope in link with the increase of the anthropogenic pressures (land consolidation, implementation of the drain network, ditches design), (ii) to track the origin of sediment reaching the pond, (iii) to identify and quantify the parameters influencing bank erosion, that is one of the main source of sediment transfers
Guillou, Nicolas. "Rôles de l'hétérogénéité des sédiments de fond et des interactions houle-courant sur l'hydrodynamique et la dynamique sédimentaire en zone subtidale - applications en Manche orientale et à la pointe de la Bretagne". Phd thesis, Université de Bretagne occidentale - Brest, 2007. http://tel.archives-ouvertes.fr/tel-00376679.
Cannon, David Engelder T. "The correlation between joint orientation and transport direction in the Sawtooth Salient, northern Montana". 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-3652/index.html.
MacVicar, Bruce J. "On turbulence and the formation of riffle-pools in gravel-bed rivers = La turbulence et la formation des seuils-mouilles dans les rivières à lit de gravier". Thèse, 2006. http://hdl.handle.net/1866/17617.
Santos, Sérgio Queirós de Sá. "O poder determinativo do empregador nas mudanças de local de trabalho e de horário de trabalho e os efeitos destas no quadro das despesas com os transportes". Master's thesis, 2019. http://hdl.handle.net/10071/18905.
The principle of contractual stability (or pacta sunt servanda) is not intended to be merely a legal jargon in the context of subordinate labor relations, it must have an effective utility, which may, as a last resort, condition the decision making of the subject contractual beneficiary of heterodisability counterparty at a particular location and for certain periods of time. In this type of legal relationship, which is originally unbalanced, it is vital that the various legal mechanisms for safeguarding the worker's interests are duly comprehensible in the sense of their full use, according to criteria of reasonableness, in absolute favor of the necessary rebalancing of the legal and labor position of the parties. Consequently, the present study focuses on the theme of changes in workplace and working hours decided by the employer in the use of regular and legally recognized power of direction and, with greater focus, on the consequences of the impact suffered by the worker on the aforementioned changes, either by reducing or increasing transport costs. It is understood that this theme, especially in relation to the mechanisms for calculating the increase in transport expenditure, deserves special attention, considering the (little) treatment given by the doctrine to the outstanding subject matter, recognizing, however, the way forward. jurisprudence in this respect. It is considered that this approach to the conditions of entitlement to receive the increase in transport costs may have the potential to point to existing practices of solving existing or existing cases in the context of individual employment relationships.