This diploma thesis describes study of interconnection of Letohrad and Lanškroun water distribution systems. The thesis contains an overview of legislative regulations and technical standards related to the construction, design and directional solution of water supply systems. Following that, there is the description of the current state of the affected water mains. Next part is the design of interconnection including hydraulic analysis in using Epanet 2.0 software. The study contains several variants of the solution. The economic assessment is included.

This thesis deals with stochastic water demand modellling in the water supply network. In the opening section, a research is created, where two different approaches to stochastic modelling of water consumption are presented. The practical part describes the creation of a deterministic hydraulic model and its calibration. Generated stochastic water demand patterns with a small time step of 1 minute, are then inserted into this model. Each household is assigned with a unique water demand pattern. Then a hydraulic analysis was done. A comparison of deterministic and stochastic approaches is presented at the end of the thesis. The comparison shows, that small-time step modelling does not have a big impact on the pressure ratios in the water supply network, but has a huge impact on the maximum flows and speeds occurring in links of the hydraulic model.

This Diploma thesis deals with minimum night flows issue. Basic findings about minimum night flows were summarized in the introductory part of thesis. Findings like the minimum night flow components, affecting parameters and used methodologies for assessment of minimal night flows. In the practical part of this thesis was this knowledge applied to real water distribution system in the municipality Hrádek u Sušice. The part of this thesis was also determinate the measurement accuracy of used water meter, which was formerly installed at the outlet in the Hrádek water tank. Measurement errors was determinate for the flow values, that are close to the real measured minimum night flow data in the water distribution system in municipality Hrádek u Sušice.

Das Auftreten von Braunwasser in Trinkwasserverteilungsnetzen ist eine Beeinträchtigung der Trinkwasserqualität, die durch mobilisierte partikuläre Ablagerungen verursacht wird. Die Partikel gelangen durch verschiedene Prozesse, wie z. B. der Korrosion metallischer Leitungen und den Eintrag am Wasserwerk, kontinuierlich in sehr geringen Massenströmen in das Rohrnetz. Durch die Akkumulation der Partikel an Rohroberflächen können sich Ablagerungsmengen bilden, die bei ansteigenden Strömungsgeschwindigkeiten resuspendiert werden und zu unerwünschten Braunwassererscheinungen führen. Die vorliegende Arbeit behandelt die experimentelle Untersuchung des Transportes von Partikeln, die für Trinkwassernetze typisch sind, in Rohrströmungen. Es werden Einflussfaktoren identifiziert, die für den Partikeltransport von Bedeutung sind. Ein neu entwickeltes dynamisches Modell beschreibt den Transport von Partikeln und die Ablagerungsbildung in Rohrströmungen und vermaschten Rohrnetzen. Das Modell wurde in einer Anwendersoftware implementiert und an einem Trinkwasserverteilungsnetz für das Nachvollziehen der beobachteten Ablagerungsbildung eingesetzt. Im Vergleich zu bestehenden dynamischen Modellen werden partikelbezogene Prozesse unter Berücksichtigung der für trinkwasserbürtige Partikel und Ablagerungen typischen Eigenschaften mathematisch genauer beschrieben. Stationäre und dynamische Ereignisse bezüglich Wasserqualität und Ablagerungsbildung können jetzt durch die Berücksichtung zahlreicher zeitabhängiger Einflussfaktoren nachvollzogen werden. / The occurrence of discoloured water in drinking water distribution systems is a disturbance of the water quality, which is induced by mobilised particulate deposits. Different processes result in the continuous entry of small mass flow rates of particles into the piping, for instance the corrosion of metallic pipes as well as the entry at the water works outlet. By the accumulation of these particles, significant amounts of deposits can be formed and at higher flow rates be resuspended, which leads to unwanted events with discoloured water. This study examines the experimental investigation of the transport of particles, which are typical for drinking water distribution systems, in pipe flow. Influencing factors are identified, which are of importance for the particle transport. With a newly developed model, the transport of particles and the deposit formation in pipe flow and in piping is described. The model is implemented into a software application and deployed at a drinking water distribution system to understand the observed deposit formation. In comparison with existent dynamic water quality models, particle-related processes are described mathematically in more details, under consideration of characteristics typical for particles and deposits in drinking water distribution systems. Hence, observed steady-state and dynamic events can be followed using several influencing time-dependent factors.

Les fuites non détectées dans les réseaux d'eau potable sont responsables en moyenne de la perte de 30% de l'eau transportée. Il s'avère donc primordial de pouvoir contrôler ces fuites. Pour atteindre cet objectif, la modélisation de l'écoulement de l'eau dans les conduites en tenant compte des fuites a été formulée de différente manière. La première formulation est un système d'équations différentielles ordinaires représentant des fuites constantes, réparties uniformément le long des conduites. Le système peut s'avérer être numériquement raide lorsque des organes hydrauliques sont rajoutés. Deux méthodes implicites ont été proposées pour sa résolution : la méthode de Rosenbrock et la méthode de Gear. Les résultats obtenus montrent que le débit varie linéairement le long des conduites et que les pertes en eau par unité de longueur sont identiques sur chaque conduite. La seconde formulation prend en compte la relation entre les fuites et la pression. Un système de deux équations aux dérivées partielles a été proposé. L'EDP de transport-diffusion-réaction, contenant l'opérateur du p-Laplacien, est résolue par une méthode à pas fractionnaires. Deux méthodes ont été testées. Dans la première, la réaction est couplée avec la diffusion et dans la seconde, elle est couplée avec le transport. Les résultats indiquent que les pertes en eau ne sont pas réparties de façon homogène sur le réseau. Cette formulation décrit de manière plus réaliste les réseaux d'eau potable. Enfin, le problème du contrôle du volume des fuites par action sur la pression a été étudié. Pour cela, un problème d'optimisation est résolu sous la contrainte que la pression doit être minimale pour réduire les fuites et être suffisante pour garantir un bon service aux consommateurs. Les résultats trouvés confirment que la réduction de la pression permet de réduire le volume des fuites de façon significative et que le choix de l'emplacement du ou des points de contrôle est primordial pour optimiser cette réduction. / Leakage represents a large part, in average more than 30%, of the water supplied. Consequently, it is important to control leakage in Water Distribution System (WDS). For this purpose different methods, which take leakage into account, are proposed to model the hydraulics of WDS. The first formulation considers constant leakage in a network and leads to an ordinary differential equation. It turns out to be a hydraulic stiff problem due to valve and pump operations. This equation is solved using two methods: the first one is a generalised Runge-Kutta method and the second one the Gear method. The results show that the flow rate varies linearly along a pipe and that the water loss per unit of length is identical for each pipe. Magnitude of inertia terms has also been studied. The second formulation takes pressure-dependent leakage into account. We propose to introduce partial differential equations in order to predict more accurately hydraulic flows in WDS. Thus, the physical advection-diffusion-reaction model is presented. A nonlinear operator, called p-Laplacian, related to the diffusion is included into the model. Two resolutions of this model based on a splitting method are detailed. The results confirm that losses vary nonlinearly with pressure. Finally, the leakage-control problem is studied. For this purpose, we solve an optimisation problem with the objective to minimize the distributed volume in order to reduce leakage. The condition of sufficient pressure to satisfy consumers is imposed in this optimisation. The results prove that pressure control significantly reduces leakage and that the emplacement of the valve is important to optimise this reduction.

Management and supply of water in an urban water distribution system is a complex process, which include various complexities like pressure variations across the network depending on topography, demand variations depending on customers’ requirement and unaccounted water etc. Applying automatic control methods to water distribution systems is a way to improve the management of water distribution. There have been some attempts in recent years to develop optimal control algorithms to assist in the operation of complex water distribution systems. The difficulties involved by these hydraulic systems such as non-linearity, and diurnal demand patterns make the choice of a suitable automatic control method a challenge. For this purpose, this study intends to investigate the applicability of different controllers which would be able to meet the targets as quickly as possible and without creating undue transients. As a first step towards application of different controllers, PD and PID linear controllers have been designed for pump control and valve control in water distribution systems. Then a Dynamic Inversion based nonlinear controller has been designed by considering the non-linearities in the system. Here, different cases considering the effects of initial conditions used, linearization methods used, time step used for integration and selection of gains etc., have been studied before arriving at best controller. These controllers have been designed for both the flow control problems and level control problems. It is found that Dynamic Inversion-based nonlinear controller outperforms other controllers. It is well known that the performance of controllers is much dependent on the tuning of the gains (parameters). Thus in this study various alternative techniques such as Ziegler--Nichols rules (ZNPID), Genetic algorithms (GAPID) and fuzzy algorithms (FZPID) have been studied and a comparative study has been made Although with all the three gain tuning methods, required states have reached their target values, but the responses vary much in reaching to final targets. The self-tuned FZPID controller outperforms other two controllers, especially with regard to overshoots and the time taken to tune the gains for each problem. Further, an optimal DI controller is developed for the over determined case with more controls and less targets. Energy loss is considered as an objective function and normal DI controller equations are considered as constraints. Hence, an attempt is made to reduce the energy minimization in water distribution system by formulating an optimal control problem using optimal Dynamic Inversion concept. Finally, leakage reduction model is developed based on excessive pressure minimization problem by locating valves optimally as well as by setting valves optimally. For this purpose, optimization problem is solved using Pattern search algorithms and hydraulic analysis is carried out using EPANET program.

Research has shown that mixing in cross-junctions in water distribution systems is far from perfect, and that the entering fluids bifurcate from each other rather than mix. The purpose of this thesis is to study the behaviour of two fluids entering a cross-junction in a water distribution system. In this context, experimental tests and numerical simulations are performed in order to produce and test the mixing at cross-junctions. This study focuses on cross-junctions with equal pipe diameters, with flows that can vary from laminar to turbulent. The fluids are pure water and tracer. Different tracer materials with various flow configurations were tested experimentally and numerically. Firstly, an experimental study of mixing in cross-junctions was performed at the TZW: DVGW-Technologiezentrum Wasser (German Water Center) in Dresden. This experimental study pro-vides an overview of the parameters that can affect the mixing in cross-junctions, and is used to validate the numerical simulations. Different numerical approaches for modelling the mixing in cross-junctions are presented. The simulations use an existing commercial CFD code, ANSYS CFX 19.1, and are also extensively validated using experimental and numerical results from other researchers. In ANSYS CFX there are several models that can be used to simulate the mixing of two fluids. In this study both fluids are considered to be isothermal incompressible and without phase change. Two mixing models are tested: the additional variable model and the multi-component model. The three-dimensional models use RANS turbulence models and LES simulations. The parameters of the numerical setup were investigated carefully in order to study their effect on the results. Furthermore, the effect of changing the turbulent Schmidt number in the RANS simulations was extensively studied, and the results are compared with the experimental results. The accuracy of using Large eddy simulation to simulate mixing in cross junction is also tested, taking into consideration the required mesh resolution and the turbulence in the initial bound-ary conditions. This work presents an applicable numerical approach to simulate the fluid behaviours in cross-junctions. Using this approach, the effect of different parameters is tested, such as: Reynolds number, pipe diameter, mixing time, diffusivity and density difference. The results produced using the numerical approach revealed that one of the main parameters that affect the mixing is the density difference. It has a great effect on the outgoing concentration in cross-junctions, and the mixing behaviour changes when the tracer material and the flow regime are changed. The used approach will help to investigate the effect of various flow parameters on the mixing in cross-junctions. Based on the data set of this study, an empirical conceptual model for mixing in cross-junction is also presented using multiple regression, and there is potential for this model to be further developed in combination with experimental and numerical studies.:Abstract Kurzfassung Nomenclature List of Figures List of Tables 1 Introduction and Literature Review 1.1 Introduction 1.2 Literature Review 1.2.1 Transport in water distribution system 1.2.2 Mixing in pipe junctions 1.3 Research problems 1.4 Research methodology and objectives 2 Theoretical Background 2.1 Basic equations and terms in pipe hydraulic 2.1.1 Conservation of mass (the equation of continuity) 2.1.2 Conservation of momentum (the Navier-Stokes equations) 2.1.3 Contaminant transport (transport equation) 2.1.4 Reynolds number 2.1.5 Flow development in pipes 2.1.6 Velocity distribution in pipe flows 2.1.7 Definition of concentration and mass fraction 2.1.8 Viscosity 2.2 Turbulence and modeling 2.2.1 Spatial discretization methods 2.2.2 Turbulence models 2.2.3 Direct numerical simulation (DNS) 2.2.4 Reynolds averaged Navier-Stokes Equations (RANS) 2.2.5 Large eddy simulation 2.3 Modeling of mixing in ANSYS CFX 2.3.1 Additional variable 2.3.2 Multi-component flow model 2.3.3 Two-phase flow model 2.4 Mixing in cross-junctions (available models) 2.4.1 Complete mixing model 2.4.2 Bulk advective mixing model (BAM) 2.4.3 BAM-Wrap mixing model 2.4.4 Shao mixing model 3 Experimental Study 3.1 Introduction 3.2 Description of the model network 3.3 Results and discussion 3.3.1 Turbulent flow experiments 3.3.2 Laminar flow experiments 3.3.3 The interpolation of the experimental results 3.4 Conclusion 4 3D Numerical Study using ANSYS CFX 4.1 Introduction to ANSYS CFX 4.1.1 Model setup in ANSYS CFX 4.1.2 Modeling of mixing in cross-junctions 4.2 Additional variable model 4.2.1 Application of Reynolds averaged Navier-Stokes simulation 4.2.2 Sensitivity analysis of URANS simulations 4.2.3 Application of the large eddy simulation 4.2.4 Summary 4.3 Multi-component flow model 4.3.1 Setup of the multi-component simulation model 4.3.2 Results and discussion 4.4 Summary 5 Mixing Model for Cross junction 5.1 Introduction 5.2 Parameter sensitivity Analysis 5.2.1 The influence of changing the Reynolds number 5.2.2 The influence of changing the pipe diameter 5.2.3 The influence of the inflow and outflow ratios 5.2.4 The influence of changing the tracer properties 5.2.5 The influence of the pipe roughness 5.3 Conceptual model for mixing in cross junction 6 Summary 7 Outlook References APPENDIX A APPENDIX B / Frühere Forschungsergebnisse haben gezeigt, dass das Vermischen von gelösten Substanzen in Rohrkreuzen in Wasserversorgungssystemen alles andere als perfekt ist und wenn zwei Flüssigleiten in einem Rohrkreuz eintreten, trennen sie sich eher voneinander anstatt sich zu vermischen. Das Ziel dieser Forschungsarbeit ist es, das Verhalten von zwei Flüssigkeiten in einem Rohrkreuz zu untersuchen. In diesem Zusammenhang werden experimentelle Unter-suchungen und numerische Strömungssimulationen durchgeführt, um das Vermischen an Kreuzungspunkten in Wasserversorgungssystemen zu untersuchen. Diese Arbeit konzentriert sich auf Rohrkreuzen mit gleichen Rohrdurchmessern in Strömungen, die von laminar bis turbulent variieren können. Verschiedene Eigenschaften der Flüssigkeiten mit verschiedenen Strömungskonfigurationen wurden experimentell und numerisch getestet. Zunächst wurden im TZW (DVGW-Technologiezentrum Wasser) die experimentellen Untersuchungen zum Mi-schen in Rohrkreuzungen durchgeführt. Die durchgeführten experimentellen Untersuchungen bieten einen Überblick über die Parameter, die das Mischverhältnis in Kreuzungspunkten be-einflussen können, und werden zur Validierung der numerischen Simulationen verwendet. Verschiedene numerische Ansätze zur Modellierung des Vermischens in Rohrkreuzen werden vorgestellt. Die 3D-numerische Strömungssimulationen verwenden einen vorhandenen kommerziellen CFD-Code, ANSYS CFX 19.1, und werden auch anhand experimenteller und numerischer Ergebnisse anderer Forscher umfassend validiert. In ANSYS CFX gibt es mehre-re Modelle, mit denen das Vermischen von Flüssigkeiten simuliert werden kann. In dieser Arbeit werden beide Flüssigkeiten als isotherm, inkompressibel und ohne Phasenwechsel betrachtet. Es werden zwei Mischmodelle getestet: das Additional Variable Model und das Multi-component Model. Die 3D -Strömungsmodelle verwenden RANS-Turbulenzmodelle und LES-Simulationen. Die Parameter des numerischen Aufbaus wurden sorgfältig untersucht, um ihre Auswirkung auf die Ergebnisse zu untersuchen. Darüber hinaus wurde der Einfluss der Änderung der turbulenten Schmidt-Zahl in den RANS-Simulationen ausführlich untersucht und die Ergebnisse mit den experimentellen Ergebnissen verglichen. Die Genauigkeit der Ver-wendung einer Large-Eddy-Simulation zur Simulation des Vermischens in Rohrkreuz wird ebenfalls getestet, wobei die erforderliche Netzauflösung und die Turbulenzen in den An-fangs- und Randbedingungen berücksichtigt werden. Diese Arbeit präsentiert einen anwend-baren numerischen Ansatz zur Simulation des Fließverhaltens in Rohrkreuzen. Mit diesem Ansatz wird die Wirkung verschiedener Parameter getestet, z. B.: Reynolds-Zahl, Rohrdurch-messer, Vermischungszeit, Diffusivität und Dichteunterschied. Die mit den numerischen Mo-dellen erzielten Ergebnisse zeigten, dass einer der Hauptparameter, die das Vermischen in Rohrkreuzen beeinflussen, der Dichteunterschied ist, welcher einen großen Einfluss auf die ausgehende Konzentration in Kreuzungen hat. Der verwendete numerische Ansatz wird dazu beitragen, die Auswirkung verschiedener Strömungsparameter auf das Vermischen in Rohr-kreuzen zu untersuchen. Basierend auf dem Datensatz dieser Studie wird auch ein empiri-sches konzeptionelles Modell für das Vermischen in Rohrkreuz unter Verwendung multipler Regression vorgestellt. Dieses Modell kann in Kombination mit experimentellen und numeri-schen Studien weiterentwickelt werden.:Abstract Kurzfassung Nomenclature List of Figures List of Tables 1 Introduction and Literature Review 1.1 Introduction 1.2 Literature Review 1.2.1 Transport in water distribution system 1.2.2 Mixing in pipe junctions 1.3 Research problems 1.4 Research methodology and objectives 2 Theoretical Background 2.1 Basic equations and terms in pipe hydraulic 2.1.1 Conservation of mass (the equation of continuity) 2.1.2 Conservation of momentum (the Navier-Stokes equations) 2.1.3 Contaminant transport (transport equation) 2.1.4 Reynolds number 2.1.5 Flow development in pipes 2.1.6 Velocity distribution in pipe flows 2.1.7 Definition of concentration and mass fraction 2.1.8 Viscosity 2.2 Turbulence and modeling 2.2.1 Spatial discretization methods 2.2.2 Turbulence models 2.2.3 Direct numerical simulation (DNS) 2.2.4 Reynolds averaged Navier-Stokes Equations (RANS) 2.2.5 Large eddy simulation 2.3 Modeling of mixing in ANSYS CFX 2.3.1 Additional variable 2.3.2 Multi-component flow model 2.3.3 Two-phase flow model 2.4 Mixing in cross-junctions (available models) 2.4.1 Complete mixing model 2.4.2 Bulk advective mixing model (BAM) 2.4.3 BAM-Wrap mixing model 2.4.4 Shao mixing model 3 Experimental Study 3.1 Introduction 3.2 Description of the model network 3.3 Results and discussion 3.3.1 Turbulent flow experiments 3.3.2 Laminar flow experiments 3.3.3 The interpolation of the experimental results 3.4 Conclusion 4 3D Numerical Study using ANSYS CFX 4.1 Introduction to ANSYS CFX 4.1.1 Model setup in ANSYS CFX 4.1.2 Modeling of mixing in cross-junctions 4.2 Additional variable model 4.2.1 Application of Reynolds averaged Navier-Stokes simulation 4.2.2 Sensitivity analysis of URANS simulations 4.2.3 Application of the large eddy simulation 4.2.4 Summary 4.3 Multi-component flow model 4.3.1 Setup of the multi-component simulation model 4.3.2 Results and discussion 4.4 Summary 5 Mixing Model for Cross junction 5.1 Introduction 5.2 Parameter sensitivity Analysis 5.2.1 The influence of changing the Reynolds number 5.2.2 The influence of changing the pipe diameter 5.2.3 The influence of the inflow and outflow ratios 5.2.4 The influence of changing the tracer properties 5.2.5 The influence of the pipe roughness 5.3 Conceptual model for mixing in cross junction 6 Summary 7 Outlook References APPENDIX A APPENDIX B

Water distribution systems, electrical power transmission systems, and other civil infrastructure systems are essential to the smooth and stable operation of regional economies. Since the functions of such infrastructure systems often are inter-dependent, the systems sometimes suffer unforeseen functional disruptions. For example, the widespread power outage due to the malfunction of an electric power substation, which occurred in the northeastern United States and parts of Canada in August 2003, interrupted the supply of water to several communities, leading to inconvenience and economic losses. The sequence of such failures leading to widespread outages is referred to as a cascading failure. Assessing the vulnerability of communities to natural and man-made hazards should take the possibility of such failures into account. In seismic risk assessment, the risk to a facility or a building is generally specified by one of two basic approaches: through a probabilistic seismic hazard analysis (PSHA) and a stipulated scenario earthquake (SE). A PSHA has been widely accepted as a basis for design and evaluation of individual buildings, bridges and other facilities. However, the vulnerability assessment of distributed infrastructure facilities requires a model of spatial intensity of earthquake ground motion. Since the ground motions from a PSHA represent an aggregation of earthquakes, they cannot model the spatial variation in intensity. On the other hand, when a SE-based analysis is used, the spatial correlation of seismic intensities must be properly evaluated. This study presents a new methodology for evaluating the functionality of an infrastructure system situated in a region of moderate seismicity considering functional interactions among the systems in the network, cascading failure, and spatial correlation of ground motion. The functional interactions among facilities in the systems are modeled by fault trees, and the impact of cascading failures on serviceability of a networked system is computed by a procedure from the field of operations research known as a shortest path algorithm. The upper and lower bound solutions to spatial correlation of seismic intensities over a region are obtained.

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