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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vulnerability curves for masonry buildings affected by hyperconcentrated flows as natural disaster risk management tools for the quantification of material damage

Jara, A., Quispe, T. Y., Castillo, L. F. 06 January 2022 (has links)
The damage assessment caused by floods, earthquakes, hurricanes among others phenomenons in the world are analyzed with methodologies such as "Vulnerability curves". In Peru, disasters caused by hyperconcentrated flows are alarming due to a climatic variability such as the "El Nio Costero"phenomenon. Therefore, this research has developed vulnerability curves for 1 and 2-story confined masonry buildings in Urb. San Idelfonso, Ica - Peru; linking the variables: flow depth, associated with the event produced by heavy rains at the top of the "Quebrada Cansas"caused by the "El Nio Costero"phenomenon in 2017, and the percentage of the damage based on the methodology of the United States Army Corps of Engineers (USACE), whose formula is the repair value and total building value. The monetary amounts and items of the buildings are obtained from the RM 415-2017-VIVIENDA of the Ministry of Housing, Construction and Sanitation of Peru. The process consisted of hydrological modeling in HEC-HMS, hydraulic modeling in FLO-2D, damage percentage estimate and vulnerability curves production. Finally, the vulnerability curves for hyperconcentrated flows were contrasted with similar studies regarding curves for flooding and debris flow. The results of the investigation showed that the "El Nio Costero"phenomenon in 2017 had an economic impact of at least 1.3 million soles in Urb. San Idelfonso. In addition, at least 24 buildings had a complete damage and 21 buildings an extensive damage.
12

Hydraulic Modeling of Floods in an Open Conduit Cave

Albright, Lydia T. 16 September 2020 (has links)
No description available.
13

Hydraulic model investigation of sediment control measures at low weir river diversion works

Du Plessis, Lodewicus Johannes 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Rivers are one of the earth's major readily available sources of fresh water. Abstractions from rivers are however not without problems. Firstly, river ow is variable and to deliver a constant yield is difficult. Secondly, rivers transport sediment which will be included in the diverted ow. Sediment control at diversion works have been studied for many years and this study attempts to gain further knowledge on certain sediment control features of diversion works. Sediment control at diversion works and abstraction works is crucial to prolong the life of the mechanical components like pumps and turbines. A Commonly used diversion works design is one with a low weir and a graveltrap. The weir dams water for abstraction, which is of importance in South Africa with its variable rainfall and river ow. The study focused on the following design features of diversion works: (1) the intake angle, which is the angle at which the structure is pushed into the river, (2) the intake opening height above a datum, (3) the river ow range where sediment is sufficiently scoured from the graveltrap and (4) the efficiency and river ow range of sediment ushing through a sluice gate at the graveltrap. A Physical model study was conducted in the laboratory of the University of Stellenbosch, which consisted of designing the diversion works that were to be tested. The designs were based on guidelines from previous studies, case studies and hydraulic principles. The above mentioned features (1-4) were studied at three structures with prototype weir sizes of 2.5 m, 3.5 m and 4.5 m. The river was modelled as a straight rectangular channel with a loose bed surface, which was simulated with crushed peach pips. Sediment was also fed into the system with a conveyor belt feed system. Pumps were used to abstract water and sediment through the intake opening, during the diverted sediment tests. Flow was diverted at a specific ow rate for each structure. The diverted sediment was caught and weighed. Each structure was designed to divert sediment through one of three intake opening heights, to determine whether a higher intake opening sufficiently reduces the amount of diverted sediment. The self-scour efficiency at the graveltrap was determined with a sediment level survey in the graveltrap. From the survey a clearance ow was determined, which is the minimum river ow that clears the intake opening of sediment along its complete length. It was also determined what intake angle induces secondary ow which results in the lowest clearance ow. The sediment ushing through the sluice gate was evaluated by recording the time it takes a full graveltrap to be ushed clean at various river ow rates. The maximum river ow at which the graveltrap still ushes efficiently was determined for each structure. It was found that between the 300, 450 and 600 intake angle that were tested, the 60 0 angle yields the lowest diverted sediment ratio (DSR) over the range of structures as well as river ows tested. The tests yielded a river ow at each structure where the DSR is at minimum. During the self-scour tests of the graveltrap, it was determined that a 450 intake angle promotes better self-scour at the graveltrap. To promote both features, a 450 intake angle is suggested, as it reduces diverted sediment and has a lower risk of issues due to too large ow constriction. The intake opening height was evaluated with analysis of diverted load and concentration. The conclusions on the intake opening vary between structure sizes. In the case of the smallest structure, with a 2.5 m weir height, the improvement observed for intake openings higher than the first (lowest) were variable. In the case of the 3.5 m weir structure, the results showed three consecutive intake openings could be feasible. In the case of the 4.5 m weir structure, less improvement was observed between the highest two intakes. Flood frequency should determine whether an intake opening with top-of-inlet of 1.6 m or 3.3 m above the minimum operating level should be designed. It was observed during the sediment ushing tests that submergence of either the graveltrap wall and/or the downstream water level affects the ushing efficiency. y3/y2, which is the downstream ow depth over the contracted ow depth under the sluice gate of the graveltrap, was evaluated as an indicator of efficient ushing. The study found that a good guideline would be to ush during river ows where y3/y2 < 1, while also ensuring the ow over the graveltrap wall entrains the sediment in the graveltrap. A figure which plots the downstream ow depth over sluice gate opening size was developed to serve as an operational guideline to efficient sediment ushing. The figure shows zones of efficient and non-efficient ushing. Further, the observed sediment ushing and self-scour ranges at each structure are also represented graphically. The fact that there was designed for a specific river scenario and also the lack of varied model sediment size, limits the applicability of the findings and conclusions. / AFRIKAANSE OPSOMMING: Riviere is van die aarde se hoof, maklik beskikbare bronne van vars water. Onttrekking uit riviere is wel nie sonder probleme nie. Eerstens is rivier vloei wisselvallig en om 'n konstante lewering te handhaaf is moeilik. Tweedens, vervoer riviere sediment wat ingesluit sal wees in die uitgekeerde vloei. Sediment beheer by uitkeerwerke word al vir baie jare bestudeer en hierdie studie poog om verdere kennis te verkry oor sekere sediment beheer funksies van uitkeerwerke. Sediment beheer by uitkeerwerke en onttrekkingswerke is noodsaaklik om die lewensduur van meganiese komponente soos pompe en turbines te verleng. 'n Algemeen toegepaste uitkeerwerke ontwerp is een met n lae keerwal en gruisvangkanaal. Die keerwal dam water op, wat nodig kan wees om die lewering te handhaaf, veral met Suid-Afrika se wisselvallige reënval en rivier vloei. Die studie het gefokus op die volgende ontwerp funksies van uitkeerwerke: (1) die inlaathoek, wat die hoek is waarteen die struktuur in die rivier ingedruk is, (2) die inlaatopening hoogte bo 'n datum, (3) die rivier vloei reeks waar sediment voldoende uitgeskuur word uit die gruisvangkanaal uit en (4) die effektiwiteit en rivier vloei reeks van 'n sediment spoel aksie deur 'n sluishek in die gruisvangkanaal. 'n Fisiese model studie was onderneem in die laboratorium van die Universiteit van Stellenbosch, wat bestaan het uit die ontwerp van die uitkeerwerke wat getoets sou word. Die ontwerp is gebasseer op riglyne van vorige studies, gevallestudies en hirouliese beginsels. Die bogenoemde funksies (1-4) was bestudeer by drie strukture met prototipe keerwal hoogtes van 2.5 m, 3.5 m en 4.5 m. Die rivier was gemodelleer as 'n reguit, reghoekige kanaal met 'n los bed oppervlakte, wat gesimuleer is met fyngemaakte perske pitte. Sediment was ook in die sisteem ingevoer met 'n vervoerband voer sisteem. Pompe was gebruik om water en sediment te onttrek deur die inlaatopening tydens die uitgekeerde sediment toetse. Vloei was uitgekeer teen 'n spesifieke vloeitempo vir elke struktuur. Die uitgekeerde sediment was gevang en geweeg. Elke struktuur was ontwerp om sediment uit te keer deur een van drie inlaatopening hoogtes, om te bepaal of 'n hoër inlaatopening hoogte die hoeveelheid uitgekeerde sediment voldoende verminder. Die self-uitskuur effektiwiteit van die gruisvangkanaal was bepaal deur 'n sediment vlak opmeting in die gruisvangkanaal. Vanaf die opmeting was 'n skoonmaak vloei bepaal, wat die minimum rivier vloei is wat die inlaatopening skoon maak van sediment oor die totale lengte. Dit was ook bepaal watter inlaathoek veroorsaak sekondêre vloei wat die laagste skoonmaak vloei oplewer. Die sediment spoel aksie deur die sluishek was geëvalueer deur die tyd wat dit neem om 'n vol gruisvangkanaal skoon te spoel, teen verskeie rivier vloeitempos te bepaal. 'n Maksimum rivier vloei waarteen die guisvangkanaal steeds effektiewelik skoon spoel was bepaal vir elke struktuur. Dit was bevind dat tussen die 300, 450 en 600 inlaathoeke wat getoets is, lewer die 600 hoek die laagste uitgekeerde sediment verhouding (USV) oor die reeks van strukture, asook rivier vloeitempos wat getoets is. Die toetse het 'n rivier vloei opgelewer by elke struktuur, waar USV 'n minimum was. Gedurende die self-uitskuur toetse was dit bepaal dat 'n 450 inlaathoek beter uitskuur in die gruisvangkanaal bevorder. Om beide funksies te bevorder word 'n 450 inlaathoek voorgestel, omdat dit ook uitgekeerde sediment verminder en 'n laer risiko van probleme as gevolg van te groot vloei vernouing het. Die inlaatopening hoogte was geëvalueer met analise van die uitgekeerde sediment lading en konsentrasie. Die gevolgtrekkings oor die inlaatopening hoogte varieer tussen struktuur groottes. In die geval van die kleinste struktuur, met 'n 2.5 m keerwal hoogte, was die verbetering wat waargeneem was by inlaatopeninge hoër as die eerste (laagste) inlaat, wisselvallig. In die geval van 'n 3.5 m keerwal struktuur het die resultate getoon dat drie opeenvolgende inlaatopeninge kan uitvoerbaar wees. In die geval van 'n 4.5 m keerwal struktuur was minder verbetering waargeneem tussen die hoogste twee inlate. Vloed frekwensie moet bepaal of 'n inlaatopening hoogte met 'n bokant-van-inlaat vlak van 1.6 m of 3.3 m bo minimun bedryfvlak moet ontwerp word. Dit was waargeneem dat gedurende die sediment spoel toetse dat versuiping van die gruisvangkanaal muur en/of die stroomaf watervlak die spoel effektiwiteit beïnvloed. y3/y2, wat die stroomaf vloeidiepte oor die vernoude vloeidiepte onder die sluishek van die gruisvangkanaal is, was geëvalueer as 'n indikator van effektiewe spoel aksie. Die studie het bevind dat 'n goeie riglyn sal wees om te spoel tydens rivier vloeie waar y3/y2 < 1 is, terwyl dit ook verseker moet word dat vloei oor die gruisvang kanaal sediment meevoer in die gruisvangkanaal. 'n Figuur wat die stroomaf vloeidiepte teenoor die sluisopening grootte plot was ontwikkel om te dien as 'n bedryfsriglyn tot effektiewe spoel aksie. Die figuur toon zones van effektiewe en nie-effektiewe spoel aksie aan. Verder is die waargeneemde sediment spoel aksie en self-uitskuur reekse van elke struktuur ook grafies voorgestel. Die feit dat daar ontwerp is vir 'n spesifieke rivier scenario asook die gebrek aan variëerende model sediment grootte, beperk die toepasbaarheid van die bevindings en gevolgtrekkings.
14

Simulering av översvämningar i Nedre Dalälven / Flood simulations in the Nedre Dalälven area

Vähäkari, Antti January 2006 (has links)
<p>Mosquitoes are found in extremely large numbers in the lower parts of the River Dalälven. In the year 2000 the mosquito nuisance was especially high, resulting in foundation of the Biological mosquito control project. Since 2001 mosquito larvae are controlled by using a biological pesticide BTI (Bacillus thuringiensis ssp israelensis). The mosquito fauna in the area is dominated by flood water mosquitoes, a group of mosquitoes that are very aggressive and form new generations of mosquitoes during every single flooding event during the summer. To be able to efficiently control the mosquitoes it is essential to know the extension and locality of the flooding. A flooding event is evaluated by how high the water level will reach and at which time the top of the hydrograph is accruing. There is a need for a tool for short time prediction of flooding events in the Nedre Dalälven region. In this study a hydraulic model in the software HEC-RAS has been used, here called HEC-RAS NEDA. The hydraulic model came up with good results when predicting water surface levels. The validation process made from figures of a period with large amplitude in water levels showed that the modelled water level was within ± 0,05 m from the observed water stands. It is a stable model that can handle 100-year flows with quick changes in the flow. The correspondence is good concerning the water levels and it functions well when studying the top of the hydrograph. HEC-RAS NEDA is an accurate and easy to manage tool for prediction of flooding in the lake of Bysjön, Österviken and Färnebofjärden. Modelled results have been compared with the model made by Swedish meteorological and hydrological institute on the request of Räddningsverket. The results from the two models shows large discrepancies, probably because of low accuracy data entered into the model from Räddningsverket. Räddningsverket has used the Geographical Sweden Data height data bank´and I used the height data from a laser scanned digital terrain model. Area studies have also been made according to how the area of the water surface changes with the water stand. These studies show that during the flood in year 2000, 55 km2 was flooded based on laserscanning in Färnebofjärden.</p> / <p>Mygg förekommer i extremt stora antal i området kring nedre delen av Dalälven. År 2000 var myggplågan särskilt stor vilket medförde att projekt Biologisk Myggkontroll bildades. Myggbekämpning har bedrivits i Nedre Dalälven sedan 2001 med ett biologiskt bekämpningsmedel, Bacillus thuringiensis ssp israelensis (BTI). Områdets myggfauna domineras av så kallade översvämningsmygg, en grupp stickmyggor som är mycket aggressiva och bildar nya generationer efter varje enskild översvämning under sommaren. För en effektiv bekämpning av mygglarverna krävs att man vet översvämningens omfattning och lokalisering. En översvämning bedöms med avseende på hur högt vattenståndet når samt vid vilken tidpunkt hydrografens toppvärde inträffar. Det finns ett behov av ett verktyg som kan utföra korttidsprognoser av översvämningar i Nedre Dalälven. I denna studie har en hydraulisk modell i programvaran HEC-RAS använts, här kallad för HEC-RAS NEDA. Den hydrauliska modellen fungerar bra till att användas för prediktering av vattenstånd i Nedre Dalälven. Valideringen av modellen mot värden under en testperiod med stor amplitud i vattenståndet visade att modellerade vattenstånd var inom ± 0,05 m från de uppmätta värdena. Modellen är stabil och klarar av att hantera 100-årsflöden med snabba flödesfluktuationer. HEC-RAS NEDA är ett noggrant och lätthanterligt predikteringsverktyg för översvämningar i Bysjön, Österviken och Färnebofjärden. Överensstämmelsen är god gällande nivån av vattenståndet och den fungerar bra för att studera hydrografens topp temporärt. Modellerade resultat har jämförts med karteringar som Sveriges meteorologiska och hydrologiska institut har gjort på Räddningsverkets begäran. Resultaten skiljer sig betydligt mellan HEC-RAS NEDA och Räddningsverkets modell, troligen på grund av att Räddningsverket har stora svagheter i indata till modellen. Räddningsverket har använt Geografiska Sverige Data-Höjddata och modellen HEC-RAS NEDA är framtagen med höjddata från en digital terrängmodell baserad på laserscanning. Areella studier i GIS över hur arean av vattenspegeln förändras med vattenståndet visar att Färnebofjärden under augusti år 2000 lade 55 km2 under vatten.</p>
15

Hydraulic Model Study on the Wave-Moved Sediment

Liao, Yi-Chun 14 August 2011 (has links)
In the study, an innovative method is developed in 2-D wave flume tests to explore how much sand is set in motion by waves, and how wave-moved sediment is related to wave properties. Wave conditions on an initial sea bed slopes with grain size of about 0.1mm are varying during the experiments. Three initial bottom slopes of 1/30, 1/45, and 1/60 are analyzed in the study. The total number of waves acting is about 39,600 for each wave condition. The accumulated time of generated waves during the study is more than 1,280 hours; this is equivalent to about 2.45 million waves. The dark sands, along the observing window of the wave tank, of an initial sea bed are replaced by a slice column of white sands. The mixing caused by the waves moved dark and white sands together which generates a layer of grey sands that marks the interface of moved and unmoved white sands on the window. In some cases, three additional white sand columns are merged into the dark sand body perpendicular to the window to verify the uniformity of the moved layer in the wave crest direction. The quantity of the moved sediment is then computed and the wave-moved sediment by each wave is evaluated. Results show that the wave-moved sediment by each wave is linearly correlated to the wave breaking induced turbulent eddy viscosity, based on Prandtls mixing length model. The corresponding proportional coefficient reaches an asymptotic value as the number of acting waves is more than about 10,000. A Similar trend, but more diverse, is found when the wave-moved sediment is related to a movable parameter defined from the Shields number in which the Komars relation of bottom friction and slope is applied. However, the results indicate that the wave-moved sediment does not linearly correlate with the breaking wave power as proposed by most previous studies.
16

An Economical Analysis Of Alternative Eastern Black Sea Coastal Highway Defense Structures

Taskiran, Inanc 01 January 2003 (has links) (PDF)
In order to analyze the stability of Eastern Black Sea Coastal Highway defense structures constructed with natural stone armor layers, hydraulic model tests were performed under both breaking and non-breaking waves. Eight different alternative cross-sections of the defense structures were constructed in the wave flume in Coastal and Harbor Engineering Laboratory, Civil Engineering Department, METU. Water depth was kept constant at a depth of 7.5 m in front of the structures. Model scale, &amp / #955 / L, was calculated as 1:31.08 using Froude Law. Experiments were carried out for wave heights, H, ranging between 3 &ndash / 7 m. with a wave period ranging between 6 &ndash / 11 sec in prototype. A comparative economical analysis of the alternative cross-sections of the defense structures has proven that cost (per meter) differs almost 50% between the alternative cross-sections.
17

Two-dimensional hydraulic modeling for flood assessment of the Rio Rocha, Cochabamba, Bolivia.

Myrland, Johanna January 2014 (has links)
Historically humans have settled in river valleys, which has made flooding a natural hazard for human communities. This is also the situation in the valley of Cochabamba, which is frequently affected by floods. Therefore it is of high relevance to assess and manage the flood risk in order to reduce the impact in the affected areas. For this purpose hydraulic simulations were performed with the two-dimensional model Iber. The study area includes 17 kilometers of the main river, Rio Rocha, and its tributaries. The data used in the project was elevation data of high resolution and computed hydrographs. Field work and sensitivity analysis were performed to evaluate the result. The model was used to describe the dynamics of the Rio Rocha and its tributaries during flooding, such as flow path and water levels. The simulations showed that flooding mainly occurs in the tributaries and at eleven other sites without a clear riverbank. Most of the area affected by flooding is agricultural land, but also residential areas and infrastructure were also at risk. The flood duration shown to be longest for agricultural land, which can lead to major crop damage due to anoxic condition. Even though a smaller part of the affected area is residential land, the urbanization in this area is predicted to increase and more land may be settled in the near future.This thesis, along with other studies, highlights the importance of high resolution mesh to perform a hydraulic simulation with a two-dimensional model and the need of data to validate the result.
18

Prévisions des crues en temps réel sur le bassin de la Marne : assimilation in situ pour la correction du modèle hydraulique mono-dimensionnel Mascaret / Operational flood forecasting on the Marne catchment : data assimilation for hydraulic model Mascaret correction

Habert, Johan 06 January 2016 (has links)
La prévision des crues et des inondations reste aujourd’hui un défi pour anticiper et assurer la sécurité des biens et des personnes. En France, le SCHAPI, qui dépend du MEDDE, assure ce rôle. Les niveaux et les débits d’un cours d’eau dépendent étroitement des interactions à différentes échelles entre les précipitations, les caractéristiques géométriques du cours d’eau et les propriétés topographiques, géologiques et pédologiques du bassin versant. Les modèles hydrauliques, utilisés dans le cadre de la prévision des crues, sont entachés d’incertitudes qu’il est nécessaire de quantifier et de corriger afin de mieux anticiper l’évolution hydrodynamique du cours d’eau en temps réel. L’objectif de ces travaux de thèse est d’améliorer les prévisions de hauteurs d’eau et de débits, sur le bassin de la Marne, issues des modèles hydrauliques utilisés dans le cadre opérationnel de la prévision des crues à partir de méthodes d’assimilation de données. Ces prévisions reposent sur une modélisation mono-dimensionnelle (1D) de l’hydrodynamique du cours d’eau à partir du code hydraulique 1D Mascaret basé sur la résolution des équations de Saint-Venant, enrichie par une méthode d’assimilation de données in situ utilisant un Filtre de Kalman Étendu (EKF). Ce mémoire de thèse s’articule en cinq chapitres, trois dédiés à la recherche et les deux derniers à l’application opérationnelle. Le chapitre 1 présente les données et les outils utilisés pour caractériser le risque inondation dans le cadre de la prévision des crues, ainsi que les modèles hydrauliques Marne Amont Global (MAG) et Marne Moyenne (MM), sujets d’application des méthodes d’assimilation de données développées dans cette étude. Le chapitre 2 est dédié à la méthodologie : il traite des différentes sources d’incertitudes liées à la modélisation hydraulique et présente les approches d’assimilation de données de type EKF appliquées dans cette étude à travers la maquette DAMP pour les réduire. Dans le chapitre 3, cette approche est appliquée aux modèles MAG et MM en mode réanalyse pour un ensemble de crues ayant touché le bassin de la Marne par le passé. Deux publications ont été insérées dans ce chapitre "étude". Dans le chapitre 4, les corrections appliquées dans le chapitre 3, sont validées à partir du rejeu de la crue de 1983 en condition opérationnelle avec le modèle MM. La quantification des incertitudes de prévision et la réalisation de cartes de zones inondées potentielles y sont aussi abordées. L’application de ces méthodes d’assimilation de données pour les modèles MAG et MM en opérationnel au SCHAPI au niveau national et au SPC SAMA au niveau local est présentée dans le chapitre 5. Cette thèse s’inscrit dans un contexte collaboratif où chacun apporte son expertise : la modélisation hydraulique pour le LNHE, les méthodes numériques pour le CERFACS et la prévision opérationnelle pour le SCHAPI. L’ensemble de ces travaux de thèse a permis de démontrer les bénéfices et la complémentarité de l’estimation des paramètres et de l’état hydraulique par assimilation de données sur les hauteurs d’eau et les débits prévus par un modèle hydraulique 1D, ce qui constitue un enjeu d’importance pour l’anticipation du risque hydrologique. Ces méthodes ont été intégrées dans la chaîne opérationnelle de prévision du SCHAPI et du SPC SAMA. / Flood forecasting remains a challenge to anticipate and insure security of people. In France, the SCHAPI, wich depends on the MEDDE, takes this function. Water levels and discharges are highly dependent on interactions at different scales between rainfall, geometric characteristics of rivers and topographic, geological and soil properties of the watershed. Hydraulic models, used in the context of flood forecasting, are tainted by uncertainties which necessist to be quantified and corrected in order to better anticipate flow evolution in real time. The work carried out for this PhD thesis aims to improve water level and discharge forecasts on the Marne watershed, from hydraulic models used in the operational framework of flood forecasting using data assimilation methods. These forecasts come from a mono-dimensional (1D) hydraulic model Mascaret based on the resolution of Saint-Venant equations, improved by data assimilation methods using an Extended Kalman Filter (EKF). This thesis consists of five chapters, three dedicated to research and the two last to the operational application. The first presents data, tools and methods used to characterize the flood risk in the context of flood forecasting, as well as the Marne Amont Global (MAG) and Marne Moyenne (MM) models, subjects of application of data assimilation methods developed in this study. The second chapter covers hydraulic model uncertainties and data assimilation methodology (Kalman filter) applied in this thesis through DAMP in order to reduce them. In the third chapter, this approach is applied to the MAG and MM models for different flood events. In the fourth chapter, the April 1983 flood event allows to validate the corrections applied in the previous chapter for the MM model in an operational context. The uncertainties evaluations and the mapping of potential flooded zones are also reported. The real-time application of these data assimilation methods for MAG and MM models by SCHAPI and SPC SAMA is presented in the fifth chapter. This thesis takes place in a collaborative work where each member brings his own expertise : the hydraulic modeling for LNHE, the numeric methods for the CERFACS and operational forecasting for the SCHAPI. This thesis shows the benefits and complementarity of the evaluation of parameters and hydraulic state using data assimilation on water levels and discharges forcasted by a 1D hydraulic model, which is an important issue for the anticipation of hydrologic risk. These methods have already been integrated to the operational chain of flood forecasting of the SCHAPI and the SPC SAMA.
19

Component development for a high fidelity transient simulation of a coal-fired power plant using Flownex SE

Le Grange, Willie 25 February 2019 (has links)
Large coal-fired power stations are designed to be run predominantly at full load and optimum conditions. The behaviour of plants, operating at low load and varying conditions, is getting more and more attention due to the introduction of variable renewable generation on the grid. Consequently, the need for a fully transient high-fidelity system based model has grown, as this will enable one to study the behaviour of plants under such non-ideal conditions. This report details the development of a feedwater heater, deaerator and turbine component for such a high-fidelity transient system model using the Flownex Simulation Environment, a onedimensional thermohydraulic network solver. The components have been modelled all with the aim of using minimal design input data. The feedwater heater component model includes transient effects and thermodynamic relations to represent aspects such as heater performance, level control and transient inertia. In determining the heat transfer characteristics, the model makes use of plant-performance data and correlates the amount of heat transfer by using the feedwater mass flow as the load indicating parameter. This approach eliminates the need for specific geometrical details to calculate the effective heat transfer area. The level control is modelled by using a level representation built from using heat exchanger design methods. The turbine component is modelled by using Fuls’ Semi-Ellipse law or the pressure drop modelling and Ray’s semi-empirical method for the efficiency modelling. The model also contains transient effects, which include thermal inertia due to the shaft and casing, and rotational inertia due to the shaft. The deaerator component is modelled by adapting the model presented by Banda, and modifying the model to work under various conditions. This involved using curve fit methods in Flownex to use input data to model the pressure drop over the main condensate valve. Each of the mentioned components was validated and verified with plant data and finally packaged into a compound component which is a component consisting of a subnetwork in Flownex. These compound components further contain design inputs which are easily accessible by the user. The component models were integrated into larger networks in which various scenarios can be run. A short transient scenario was run on the low-pressure feedwater train of a specific power station. The scenario involved a turbine trip where the bled steam valves for the heaters were closed suddenly. The speed of the valves closing was however unknown and after closing the valves in approximately 10 seconds, results agreed relatively well with plant data. This illustrated the short transient capabilities of the feedwater heater component model. The three component models (feedwater heater, turbine and deaerator) were finally integrated into a regenerative Rankine cycle and was set up using minimal design data. The boiler, condenser and condensate pump were set as boundary conditions in the network but all extraction points for the network were connected. Steady-state results were obtained for various load cases and the main temperature, flow and pressure results were compared. Results agree well with plant data, even at low load conditions
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Posouzení vybrané části vodovodní sítě / Assessment of a selected part of the water supply network

Mrázek, Jan January 2021 (has links)
The aim of this thesis is to research the field of water distribution system monitoring and modeling such system. In the next section the thesis describes a part of the water distribution system which is located in Pardubice district, specifically south of town Přelouč. With knowledge from the done research a hydraulic model will be done. This model made in EPANET interface will be calibrated and verified using data, which was acquired by the administrator of the system VAK Pardubice a.s. Afterwards new pipelines will be added to simulate the future situation accordingly to the area plans of the cencerned towns. Furthermore another aim is to simulate the requirements made towards the water distribution system in the future in case all the areas in area plan will be completely used. This will result into creation of forward looking hydraulic model which will show possible weaknesses of the water distribution system. In case of any shortcomings, according measures will be designed for future use.

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