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Item Open Access Optimierung der Grundwasserbewirtschaftung unter Berücksichtigung der Belange der Wasserversorgung, der Landwirtschaft und des Naturschutzes(2006) Schneck, Alexander; Kobus, Helmut (Prof. Dr. h.c. Dr.-Ing. E.h. Ph.D.)Grundwasserentnahmen zum Zwecke der öffentlichen Trinkwasserversorgung führen in den Wassergewinnungsgebieten zur Absenkung der natürlichen Grundwasserstände und können sich daher negativ auf andere Grundwassernutzer auswirken. Sie bewirken beispielsweise Änderungen in den Standortbedingungen für die grundwasserabhängige Tier- und Pflanzenwelt und die landwirtschaftliche Nutzung. Bei der Existenz mehrerer Gewinnungsanlagen lässt sich die Gesamtentnahme auf die verschiedenen Brunnen verteilen, so dass hier eine Möglichkeit zur aktiven Steuerung der Förderraten gegeben ist. Dadurch ist es möglich, die Eingriffsintensität der Entnahme auf die anderen Nutzer zu minimieren. Doch durch die Entnahme aus verschiedenen Brunnen ergeben sich auch für die Wasserversorgung Anforderungen, beispielsweise hinsichtlich der Qualität des Mischwassers. Vor diesem Hintergrund gilt es, ein Werkzeug zu entwickeln, mit dessen Hilfe die optimalen Förderraten schnell errechnet werden können, wobei die verschiedenartigen Anforderungen der Wasserversorgung, der Landwirtschaft und des Naturschutzes berücksichtigt werden. Gleichzeitig muss aber auch der Frage nachgegangen werden, welche Gesamtförderrate optimal im Sinn einer nachhaltigen Entwicklung des Wassergewinnungsgebietes ist. Dazu wird in der vorliegenden Arbeit ein Bewertungs- und Optimierungssystem für die Grundwasserbewirtschaftung entwickelt und anhand des Langenauer Donaurieds seine Praxistauglichkeit unter Beweis gestellt. Das System nutzt die Rechenergebnisse von numerischen Grundwassermodellen und wertet diese zusammen mit anderen ökologischen und sozioökonomischen Bewertungskriterien aus. Der errechnete Gesamtnutzwert einer Bewirtschaftungsalternative erlaubt nun eine Aussage darüber, wie nah man der angestrebten nachhaltigen Lösung ist und macht verschiedene Alternativenbewertungen direkt miteinander vergleichbar. Mit Hilfe eines gekoppelten Optimierungsalgorithmus‘ lässt sich so schnell die bestmögliche Bewirtschaftungsstrategie unter vorgegebenen Randbedingungen ermitteln. Eine solch umfassende Betrachtung der Auswirkungen von Grundwasserentnahmen erfordert den Einsatz eines multikriteriellen Bewertungssystems. Bei den durchgeführten Untersuchungen hat sich das Bewertungsverfahren Composite Programming als am besten geeignet für die vorliegende Fragestellung dargestellt. Die Arbeit stellt Schritt für Schritt dar, wie die einzelnen Bewertungskriterien und Zielvorgaben zu ermitteln sind, wie die einzelnen Teilbewertungen zu einer nachvollziehbaren Gesamtbewertung gebündelt werden und wie die gewonnenen Informationen genutzt werden können, um die Grundwasserbewirtschaftung zu optimieren. Umfassend wird in der Arbeit die Sensitivität der Bewertungs- und Optimierungsergebnisse auf die einwirkenden Randbedingungen untersucht und dargestellt. Aus den Untersuchungsergebnissen werden weiterhin Hinweise zum Umgang mit den nicht objektivierbaren Parametern abgeleitet, um die Anwendbarkeit und Übertragbarkeit auf andere Gebiete zu erleichtern. Als Ergebnis der Arbeit steht ein Werkzeug zur Verfügung, mit dessen Hilfe Grundwasserentnahmen zukünftig für die Nutzergruppen Wasserversorgung, Landwirtschaft und Natur verträglicher gestaltet werden können. Ein solches Werkzeug ist insbesondere vor dem Hintergrund der in den kommenden Jahren umzusetzenden EU-Wasserrahmenrichtlinie (Vermeidung signifikanter Schädigungen grundwasserabhängiger Landökosysteme) dringend notwendig.Item Open Access Two-phase flow processes with dynamic effects in porous media - parameter estimation and simulation(2006) Manthey, Sabine; Helmig, Rainer (Prof. Dr.-Ing.)This study contributes to the understanding of dynamic effects in the capillary pressure-saturation relationship on the local scale and macroscale as well as giving an assessment as to when these effects might need to be taken into account for the evaluation of two-phase flow processes. In a general form, the rate-dependent Pc-Sw relationship as analysed here postulates that the difference between the non-wetting and wetting phase pressure minus the equilibrium capillary pressure is a linear function of the rate of change of saturation, introducing the factor of proportionality tau. This extended Pc-Sw relationship is examined in this study under three aspects. In order to identify flow regimes where dynamic effects might be of importance, a dimensional analysis of the two-phase balance equations being closed with the extended Pc-Sw relationship is carried out. In the dimensionless equations the well-known capillary and gravitational number, Ca and Gr, evolve. Moreover, the new dimensionless number Dy appears as a factor. Dy quantifies the ratio of the 'dynamic capillary force' to the viscous force. Relating Dy to Ca or Gr yields DyC, the ratio of the dynamic to the capillary equilibrium force, and DyG, the ratio of the dynamic capillary to the gravitational force. The influence of the dynamic capillary force decreases with increasing characteristic length scale in relation to the equilibrium capillary, viscous or gravitational force. Moreover, with increasing transient flow velocity, the dynamic capillary force gains in importance. A second part of this study deals with the determination of the coefficient tau on the basis of primary drainage laboratory experiments performed by GeoDelft, The Netherlands and numerical experiments. Using the laboratory experiments tau was calculated to vary between 11.0 kPas and 154.7 kPas depending on the water saturation. The coefficient increases with decreasing water saturation. For the determination of tau using numerical experiments first homogeneous domains were considered in order to test the averaging approach. The coefficient tau was found to scale proportionally to the porosity, the (saturation-weighted average) viscosity, and the squared averaging length, as well as inversely proportional to the intrinsic permeability. Parameters that describe the equilibrium Pc-Sw relationship have a minor influence on the coefficient tau. The dependence of tau on the averaging length poses a problem as its magnitude is thus not clearly bounded, making it impossible to define an REV. As a consequence, either the averaging length should relate to a bounded property or the averaging of the phase pressures as applied in this study has to be reconsidered. Moreover, two heterogeneous domains were studied, one being a simple pattern of two fine sand lenses in a coarse sand and the other a spatially-correlated random field. An influence resulting from the simple heterogeneity pattern on the coefficient is only noticeable in case the fine sand lenses are drained. The heterogeneity stemming from the spatially-correlated random field does not affect the magnitude of the coefficient. Finally, the impact on the numerical solution of the balance equations being closed with an extended Pc-Sw relationship is assessed with simulations of imbibition processes. The dimensionless numbers Dy and DyC can be consulted to assess the impact on the solution. The front width should be applied as the characteristic length scale. It is observed that for a dominance of the dynamic capillary over the viscous force, the rate of change of saturation is dampened and thus a retardation effect with respect to the cumulative mass occurs. Locally, accelerating and slowing down of the displacement can flatten a front in comparison to a reference case. Moreover, for a high influx of wetting phase a process reversal from imbibition to drainage and back occurred. If additionally the equilibrium capillary forces are diminished, oscillations in the solution might occur for a large viscosity ratio.Item Open Access Bedload transport estimation in mountainous intermittent rivers and streams(Stuttgart : Eigenverlag des Instituts für Wasser- und Umweltsystemmodellierung der Universität Stuttgart, 2023) Sadid, Najibullah; Wieprecht, Silke (Prof. Dr.-Ing.)Rivers and streams with the flow, sediment, and habitat seasonality are termed as intermittent rivers and streams (IRS). IRS are the main water bodies in arid and semi-arid regions of the world but are also found in the temperate and humid environment, where they are particularly draining headwater streams. Thus, a large part of headwater streams in the mountainous regions behave as intermittent water bodies, where the steep channel slope and a wide variety of sediment sizes add to their hydrosedimentological complexity. Bedload transport as an important sedimentological characteristic of mountainous IRS and essential for planning sediment management strategies, is far from being well understood. Often the knowledge of lowland perennial rivers is adapted to steep IRS, which may lead to an overestimation of bedload transport mainly due to the overestimation of near-bed flow characteristics. Despite the development of numerous methods for modifying near-bed flow parameters for steep IRS such as Double-averaging of Navier-Stokes equation and flow resistance methods modifications for steep IRS, their application is limited to small domains and laboratory conditions. In this research, the flow resistance, main determinant of near-bed flow characteristic is estimated using a regime channel approach. In this approach, the flow resistance is estimated on reach-scale based on the channel’s regime dimension, slope and bankfull discharge assuming an IRS is in regime state (equilibrium condition). A channel’s regime state represents a long-term average characteristic of a river and does not significantly change over time. A channel reach of a constant slope develops a certain flow resistance during its regime state development to resist the change imposed by bankfull discharge and maintain a specific regime geometry, slope, and sediment grain size. 2D- hydromorphological computer simulations are employed to simulate the development of channel regime state for several cases of initial geometries, slopes, and grain sizes by steering the flow resistance. This modifies the riverbed shear stress by the ratio of total flow resistance to grain resistance also known as relative flow resistance µ in order to account for flow energy dissipation on resistance sources such as macro-roughness elements (MRE), and bedforms. Alternatively, two cases of MRE as a main flow resistance inducer is built as non-erodible trapezoidal shapes (i) randomly distributed over the channel bed, and (ii) arranged in cascade bedforms are used in regime channel simulations. MRE protects the channel by reducing the exposed riverbed to erosion and changing the flow characteristics in their vicinity. Regime channel simulations are performed on artificial channels of initial slopes between 0.0% to 10% and initial dimensions of 5.5 m x 200 m and 16.5 m x 200 m resembling a fixed (laboratory) and an extended-width (natural wide channel) condition. Three channel slope combination cases representing a natural channel reach which can be composed of one or more constant slope stretch are also studied beside single slope channels. Steady state simulations are performed for six sediment grain size (GSD) sets, which cover a wide spectrum of naturally occurring sediment sizes. The simulation results show a power-law relationship between µ and regime channel slopes for all channel dimensions, reach combinations, GSD, initial slopes and with (R1) and without sediment feeding (R). The increase in relative flow resistance (µ) with regime channel slope is well reproduced in form of bedforms. Regime channels developed step-pool to cascade bedforms for steep slopes and plane- to riffle bed for gentle slopes channels. The relationship between µ and regime slope derived using regime channel simulation approach exhibits good agreement with some field measurement of flow resistance for mountainous rivers and streams. The approach is applied on two IRS case studies with observed data in Kabul River basin, Afghanistan to estimate bedload transport. The relative flow resistance resulted from models calibration showed good agreement with those derived from test channels regime development simulation. The outcome of channel regime simulation with presence of MRE as geometrical shapes produced a logarithmic-law with a horizontal asymptote relationship between MRE concentrations and channel regime slopes. Similar results are also reported from flume experiments that the ratio of drag to total shear stress increases rapidly when the MRE are sufficiently distant. Regime channels develop micro-channels around MRE, where the bulk of bedload transport occur. For MRE arrangements as cascades, the results show a power-law relationship between channel regime slope and step-pool dimensions λ = LD/DB. The results obtained are in good agreement with field measurement of naturally occurring and artificially built λ relationship with SR. Future studies can further enrich the validation of this approach by applying it to other study sites. Present modelling tools have their limitations when dealing with strong geometries which is often the case for mountain rivers, therefore, improvement in modelling techniques is required to flexibly deal with abrupt changes in riverbed geometry for instance when implementing MRE as main flow resistance inducer.Item Open Access Diskretisierungsansätze zur Modellierung von Strömungs- und Transportprozessen in geklüftet-porösen Medien(2003) Neunhäuserer, Lina; Helmig, Rainer (Prof. Dr.-Ing.)Im Zusammenhang mit z.B. der Trinkwassergewinnung aus Kluftaquiferen oder der Beurteilung von Deponiestandorten kommt der Simulation von Strömungs- und Transportprozessen in geklüfteten Systemen eine große Bedeutung zu. Die oft sehr unterschiedlichen hydraulischen Eigenschaften von Kluft und umgebender Gesteinsmatrix prägen das Strömungs- und Transportverhalten stark. Unter gesättigten Bedingungen können Klüfte bevorzugte Fließwege darstellen, während die umgebende Gesteinsmatrix dagegen häufig wie ein Speicher wirkt. Diese gegensätzlichen physikalischen Prozesse müssen bei der numerischen Simulation von dem zur Anwendung kommenden Modellkonzept mit den dazugehörigen Diskretisierungsverfahren in Abhängigkeit von der Fragestellung hinreichend erfasst werden.Vor diesem Hintergrund werden in der vorliegenden Arbeit Diskretisierungsansätze für die Simulation von Strömungs- und Transportprozessen in geklüftet-porösen Medien entwickelt und untersucht. Als Grundlage wird der kombinierte Modellansatz verwendet. Die Klüfte werden dabei üblicherweise mit Elementen niedrigerer Dimension diskretisiert als die Matrix. Dieses Vorgehen wird als niederdimensional bezeichnet. Dabei ist allerdings die lokale Flusserhaltung am Kluft-Matrix-Übergang nicht gewährleistet und der zugrunde liegende physikalische Prozess gegebenenfalls nicht richtig erfasst. Um hier eine bessere Prozessdarstellung zu erreichen, wird als neuer Ansatz eine äquidimensionale Formulierung vorgestellt, der Kluft und Matrix mit Elementen gleicher Dimension beschreibt. Es werden eine Reihe etablierter numerischer Diskretisierungsansätze aus dem Bereich der Finite-Elemente-und Finite-Volumen-Verfahren hinsichtlich ihrer Eignung sowohl für die nieder- als auch für die äquidimensionale Approximation der Strömungs- und Transportprozesse in beliebig geklüfteten Systemen analysiert. Als Resultat dieser Untersuchung wird für die Strömung ein Boxverfahren und ein gemischt-hybrides Finite-Elemente-Verfahren, für den Transport ein Boxverfahren mit unterschiedlichen Upwinding-Strategien ausgewählt. Die im Rahmen der Modellbildung implementierte und verwendete Software für Kluft- und Netzgenerierung und für die numerische Diskretisierung wird vorgestellt. Die Anwendbarkeit und die Eigenschaften sowohl der äquidimensionalen im Vergleich mit der niederdimensionalen Formulierung als auch der gewählten numerischen Diskretisierungsverfahren im Hinblick auf diese beiden Ansätze wird anhand von Modellbeispielen von ansteigend geometrischer Komplexität diskutiert. Die Ergebnisse zeigen, dass die Verwendung eines äquidimensionalen Ansatzes bei langsameren Systemen mit Klüften quer zur Hauptströmung deutliche Auswirkungen auf die approximierte Lösung zeigt, während bei schnelleren Systemen eher lokale Effekte auftreten. Der Einsatz gemischt-hybrider Finiter Elemente ist bei äquidimensionaler Formulierung sinnvoll. Das für den Transport verwendete Boxverfahren mit Streamline Orientation in der Matrix erzeugt deutlich steilere Konzentrationsfronten im Matrixbereich als mit reinem Fully Upwinding.Item Open Access Analysis of the influence of structures and boundaries on flow and transport processes in fractured porous media(2005) Süß, Mia; Helmig, Rainer (Prof. Dr.-Ing.)This thesis is focused on the evaluation of tracer-breakthrough curves for the purpose of identifying domain structures and material properties. Examples of such structures are single fractures, fracture systems, layers or lenses. The investigations are based on the analysis of numerically modelled as well as measured data of domains on laboratory-scale. The numerical simulations are conducted using a flexible model set-up allowing variations of domain characteristics as well as of boundary conditions. First, the influence of impervious domain boundaries on flow and transport measurements is investigated. Initially, the general influence of boundaries on selected flow and transport variables is discussed. Subsequently, the significance of the influence of, on the one hand, impervious boundaries, and on the other hand, structures on the variation of selected variables of flow and transport is compared. The analysis is based on simulated tracer-breakthrough curves of one homogeneous system with exclusively boundary influence and of ensembles of heterogeneous systems with structure influence only. It is concluded that the influence of the boundaries is of the same magnitude as the influence of the structures. Finally, the sensitivity of tracer-breakthrough curves to structure variations depending on the existence of boundaries is investigated. For this purpose, simulation results from heterogeneous systems with and without impervious boundaries are compared. It is concluded that, in general, the sensitivity of flow and transport results is increased if the domain is limited by impervious boundaries. The investigations show that general predictions of the influence of boundaries on the flow and transport behaviour can only be made in exceptional cases for domains with very simple structure distributions. For more complex domains, boundary effects must be investigated individually in order to exclude unfavourable experimental or numerical set-ups and in order to interpret measured or simulated data correctly. The work presented demonstrates new ways of analysing different aspects of the boundary influence. Second, possibilities and limitations of structure identification are investigated. Based on three groups of test cases of varying characteristics, typical shapes of tracer-breakthrough curves are discussed and the fundamental mechanisms that lead to a certain curve shape are identified. Using the experience gained, an approach which is based on the shape of tracer-breakthrough curves and the initial arrival times, is developed for locating structures and approximating their permeabilities. The identification result is first assessed by applying the approach to the known test cases. Subsequently, the applicability to unknown artificial as well as real cases is tested. For domains containing block-shaped structures the new approach yields satisfying results for both artificial and real domains. For domains containing a few significant fractures, it is a useful support for approximating the structure distribution. Despite deviations, the fundamental characteristics are approximated correctly. The newly developed approach should be considered as one possible method to be used in combination with all other available data in order to obtain accurate identification results.Item Open Access Evaluation of life safety risks related to severe flooding(2009) Ehsan, Saqib; Wieprecht, Silke (Prof. Dr.-Ing.)The flooding risk has always been considered to be very important for the risk safety management of dams. The extreme flooding downstream of a dam could be either due to dam failure or sometimes it can occur without failure. In both cases, it poses serious risks to people and property downstream of the dam. In this study, the risk assessment for the Jhelum river valley downstream of Mangla dam has been carried out. Mangla dam is one of the large earth and rock-fill dams in the world. The height of the main dam is about 125 m above riverbed after the raising of about 9.15 m (30 ft) which was planned to be completed in 2008. For this research, Mangla dam has been considered with raised conditions. The main aim of this research is to develop an improved method for loss of life estimation due to extreme flooding (with and without dam failure) downstream of a dam and to analyze the pattern of impacts depending on the downstream valley shape on possible life loss. The project reach is about 329 km long downstream of Mangla dam including different hydraulic structures. It has been modeled for unsteady flow conditions by using MIKE 11 (1D). Different catastrophic flooding scenarios with and without dam failure have been taken into consideration. Based on flood routing results, the flood severity indication has been done downstream of the dam for different flooding scenarios. In order to have more meaningful and realistic results, a new criterion for flood severity has been developed. For more precise and realistic estimates of possible life loss due to extreme flooding downstream of the dam, an improved and elaborate loss of life (LOL) estimation method has also been developed and loss of life (LOL) has been estimated for different flooding scenarios. In order to generalize the LOL results of Jhelum river valley for other river valleys in the world, new valley shapes have been produced according to the suggested changes and hydraulic modeling under unsteady flow conditions for different flooding scenarios has been carried out. This study provides new useful guidelines for the better risk assessment of existing and planned dams in Pakistan and in other parts of the world.Item Open Access Stochastic and hydrological modelling for climate change prediction in the Lima region, Peru(2015) Chamorro Chávez, Alejandro; Bárdossy, András (Prof. Dr. rer. nat. Dr.-Ing.)Climate change has been an important field of research in the past years and certainly is a major concern in the present time. It involves a broad spectrum of subjects and significant different time scales, ranging from decades to thousands or millions of years. Generally speaking, in a climate change scenario a change in the pattern, average or extreme conditions of some variables is observed, and this can be due to many different causes as changing processes in the earth, human activities or extra terrestrial induced factors. This study concentrates on the influences on the climate due to human activities and focuses on the hydrological response to these influences or changes as a primarily goal, for the next few decades. The main motivation is the vulnerability and scarcity of the water availability in the capital of Peru, Lima, and how the area under study will respond to a change in the climate. An important focus of analysis in order to reduce the uncertainty in the predictions is the errors that appears when modeling a given variable or set of variables. This issue is addressed first in regionalization of precipitation and second in the calibration of hydrological models in which a robust parameter estimation is performed. In the first issue concerning to regionalization, External Drift Kriging is applied. In this part of the work the results of regionalization are analyzed with focus on the errors and systematic errors which appear during the modeling. The main goal here is the reduction of these errors through some proposed transformations. Here, three approaches are suggested, namely smoothing of the digital elevation model (DEM) considering a symmetric area, power transformation and smoothing considering a non symmetric area. The second issue concerning the uncertainty in the estimations (discharge) was addressed two-fold, namely by optimizing the objective function by means of a heuristic optimization procedure based on Monte Carlo simulation, and by means of a robust parameter estimation (ROPE) algorithm developed quite recently by Bárdossy and Singh, which in general terms can be used as a general multivariate optimization procedure. The algorithm offers a way of finding a set of “good” parameter vectors, which among other characteristics, are transferable in time. The final result comprises an ensemble of estimations for expected discharge variations accounting for the uncertainty in parameterization and processes description in the models. In this study HVB and HYMOD models are used. The assessment of the impact of climate change in precipitation and temperature is carried out by a statistical downscaling procedure based on a quantil-quantil transformation. Here the information given by the Global Climate Models (GCMs) outputs are transferred to the local scale. Two different GCMs and three scenarios are used in this step. This permitted the definition of a range for the expected future variations for temperature and precipitation. The last chapter of the study addresses the assessment of the discharge in the short term. The goal here is to “infer” the outcome of a random variable (discharge) in the next time step by taking information from past observations (previous steps). As we can regard the observations (time series) as a realization generated from a stochastic process, we can address this issue from a stochastic point of view. The task is addressed first by considering some of the existing autoregressive models (AR process), and second by considering a Copula-based autoregressive model. In order to perform the Copula-based autoregressive model, a given time series (modelled discharge) was transformed into three vectors representing the same original time series but shifted in time. A three dimensional Copula was then fitted to the univariate distributions. For this, a Gaussian model as well as a Beta kernel model expressed in terms of the Beta function was considered.Item Open Access Data processing and model choice for flood prediction(Stuttgart : Eigenverlag des Instituts für Wasser- und Umweltsystemmodellierung der Universität Stuttgart, 2022) Herma, Felix; Bárdossy, András (Prof. Dr. rer. nat. Dr.-Ing.)Item Open Access Implementierung und Anwendung netzfreier Methoden im Konstruktiven Wasserbau und in der Hydromechanik(2009) Zöllner, Frank; Giesecke, Jürgen (Prof. em. Dr.-Ing. habil. Dr.-Ing. E.h.)Die gängigen, heute in Forschung und Ingenieurpraxis verbreitet Anwendung findenden numerischen Methoden, beispielsweise die Methode der Finiten Elemente (FEM) oder der Finiten Volumen (FVM), basieren auf einem Rechennetz. Die Erzeugung dieses Rechennetzes stellt trotz des hohen Entwicklungsstandes heute erhältlicher Softwarepakete oft denjenigen Teil einer numerischen Analyse dar, der die meiste Bearbeitungszeit in Anspruch nimmt. Zwar stehen heute hoch entwickelte automatische Netzgeneratoren zur Verfügung, jedoch liefern diese bei komplizierten Geometrien häufig kein zufrieden stellendes Ergebnis, womit das erhaltene Rechennetz einer intensiven Nacharbeit bedarf. Insbesondere bei sich dynamisch ändernder Geometrie, beispielsweise im Fortschreiten eines Risses gegeben, fällt dies besonders ins Gewicht, da eine vollständige Neuvernetzung für jeden einzelnen Zeitschritt des Rechenganges erforderlich ist. Eine wirkliche Automatisierung ist dann nicht möglich. Darüber hinaus stellen Teilchenablösungen und wechselnde Material- oder Zustandsübergänge wie zwischen trockenen und benetzten Zonen, wasserbaulichen Problemstellungen inhärent, hohe Hürden für herkömmliche numerische Methoden dar. In gewissem Sinn widerspricht ein starres Rechennetz der Natur einer Flüssigkeit. Damit ist der Einsatz eines hierauf basierenden Verfahrens in Hydromechanik und Konstruktivem Wasserbau eingeschränkt. Die vorliegende Arbeit schlägt Lösungen auf Basis netzfreier Methoden vor. Diese benötigen kein Rechennetz und sind dadurch den genannten Einschränkungen nicht unterworfen. Der im Konstruktiven Wasserbau stets präsenten Interaktion zwischen Festkörper und Flüssigkeit, beispielsweise im Zuge der Standsicherheitsuntersuchung einer Talsperre eine zentrale Rolle spielend, wird durch die Kombination zweier netzfreier Methoden Rechnung getragen: Die Elementfreie Galerkin Methode (EFGM) wurde zur Analyse des Talsperrenkörpers hinsichtlich Verformungen, Spannungen und Rissbildung implementiert und eingesetzt. Betont wird hierbei die numerische Umsetzung bruchmechanischer Vorgänge als Grundlage nach DIN 19700 zu führender Nachweise bestimmter Bemessungssituationen, da die Elementfreie Galerkin Methode hier besondere Vorteile gegenüber der Methode der Finiten Elemente aufweist. Zur Abbildung verbundener hydrodynamischer Prozesse, insbesondere des instationären Wasserdrucks infolge Erdbebens, wurde ein Programmmodul auf Basis der Methode der Smoothed Particles Hydrodynamics (SPH) entwickelt und angewandt. Unter Kombination beider Methoden werden mögliche Ansätze maßgeblicher Talsperren-Nachweise aufgezeigt. Darüber hinaus werden zahlreiche weitere Simulationen vorgestellt, welche das breite Anwendungsspektrum netzfreier Methoden in Konstruktivem Wasserbau und Hydromechanik sowie in allgemeineren Fragestellungen der Mechanik veranschaulichen.Item Open Access Investigations on functional relationships between cohesive sediment erosion and sediment characteristics(Stuttgart : Eigenverlag des Instituts für Wasser- und Umweltsystemmodellierung der Universität Stuttgart, 2021) Beckers, Felix; Wieprecht, Silke (Prof. Dr.-Ing.)