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Development of a high-resolution 1D/2D coupled flood simulation of Charles City, IowaMoore, Matthew Roger 01 May 2011 (has links)
The development of a high-resolution coupled one-dimensional/two-dimensional hydrodynamic model of Charles City, Iowa is presented in this study as part of a larger Iowa Flood Center initiative to create a library of steady inundation maps for communities in Iowa which have a high risk of flooding. Channel geometry from bathymetric surveys and surface topography from LiDAR were combined to create the digital elevation model (DEM) used in numerical simulations. Coupled one- and two-dimensional models were used to simulate flood events; the river channel and structures were modeled one-dimensionally, and the floodplain was modeled two-dimensionally. Spatially distributed roughness parameters were estimated using the 2001 National Land Cover Dataset. Simulations were performed at a number of mesh resolutions, and the results were used to investigate the effectiveness of re-sampling simulation results using higher- resolution DEMs. The effect of removing buildings from the computational mesh was also investigated. During 2011, the stream channel geometry is being changed as part of a recreational park in downtown Charles City. After incorporating the planned changes to the stream channel, the model was used to create a library of steady inundation maps which are available on the Iowa Flood Center website.
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Hydrodynamický model soutokové oblasti Svitavy a Svratky / Hydrodynamic model in the area of the confluence of the rivers Svitava and SvratkaHalaška, Ondřej January 2018 (has links)
Master's thesis deals with present state assessment of flood hazard on rivers Svitava and Svratka in the southern part of Brno. Flood discharges Q5, Q20, Q100 and Q100N were solved using coupled 1D/2D numerical model. All results were evaluated as maps of hazard.
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Studie protipovodňových opatření v lokalitách Pisárky a Staré Brno na Svratce / Feasibility study of the flood protection measures in the localities of Pisárky and Staré Brno at the Svratka riveCharvát, Jan January 2017 (has links)
This thesis deals with the assessment of the current state of flood protection in Brno, Pisárky and the Staré Brno district on the Svratka river at km 37.053 to 41.116 and the subsequent design and assessment of flood protection measures. Hydraulic calculations were carried out using the coupled 1D / 2D numerical model of water flow to pass peak flows Q1, Q5, Q20, Q100 a Q100 unaffected. The results are processed in the form of inundation maps and drawing documentation.
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Lithospheric structure in Central Europe : integrated geophysical modelling / Détermination d’un modèle lithosphérique en Europe centrale : modélisation géophysique intégrée / Stavba litosféry v Strednej Európe : integrované geofyzikálne modelovanieGrinc, Michal 24 October 2013 (has links)
L'objectif principal de cette thèse est d'acquérir de nouvelles connaissances sur la structure tectonique et la lithosphérique de la région des Carpates et du bassin pannonien. Nous avons appliqué trois méthodes différentes: modélisation 1D,modélisation 2D géophysique intégrée et inversion 3D pour atteindre cet objectif. Ces méthodes sont similaires concernant les bases de données utilisées, mais diffèrent par le traitement et l'interprétation de données. Au début, nous avons appliqué la modélisation automatique 1D pour obtenir un premier aperçu de la région étudiée. Deuxièmement, nous avons appliqué la modélisation 2D intégré de la lithosphère qui combine l'interprétation du flux de chaleur,du géoïde, de la gravité et des données topographiques de la région des Carpates et du bassin pannonien et des régions avoisinantes. Cette approche est capable de contraindre des structures lithosphériques compliquées de la région étudiée mieux que l'interprétation de chaque donnée indépendamment. Nous présentons quatre modèles intégrés 2Dde la lithosphère dans la région des Carpates et du bassin pannonien et des régions avoisinantes. Enfin, sur la base de l'algorithme d'inversion 3D, nous présentons les modèles géophysiques de la lithosphère dans la région des Carpates et du bassin pannonien. L'algorithme calcule la structure de la densité lithosphèrique par l'inversion conjointe de la gravité, géoïde et données topographiques basé sur une approche bayésienne. Les modèles sont basés sur différents ensembles de données d'entrée et ils sont contraints par différentes données a priori. Sur la base de notre modélisation, nous ne pouvons pas confirmer l'amincissement extrême (moins de 70 km)de la lithosphère du bassin pannonien proposé par d'autres auteurs. D'autre part, les résultats montrent la tendance à l'augmentation de l'épaisseur lithosphérique de Carpates d'occidentales vers de Carpates de l'est ce que confirme les théories antérieures sur la propagation du processus de subduction. Nous avons obtenu des résultats controversés dans la région des Carpates du sud.Les résultats basés sur l'inversion 3D montrent une lithosphère extrêmement mince dans ce domaine mais les résultats basés sur la modélisation 2D intégrée ne supportent pas cet amincissement. Cependant, les deux méthodes indiquent qu'il est plausible que la plateforme Moésienne soit courbée et chevauchée sous les Carpates du sud. Dans le modèle 3D, le bord sud-est du bassin Pannonien montre une lithosphère inattendue et étonnamment mince. Puisque la zone est assez grande, nous pouvons exclure un effet de flexion, par conséquent, cette région pourrait être potentiellement intéressante pour une recherche plus approfondie. / The main aim of this thesis is to gain new knowledge about the lithospherical structure and tectonics of the Carpathian–Pannonian Basin region. We applied three different methods: 1Dautomatic modelling, 2D integrated geophysical modelling and 3D inversion to achieve this goal.These methods are similar concerning the used databases but differ by used processing andinterpretation. At first we apply 1D automatic modelling to get a very first overview of thestudied region. Secondly, we apply 2D integrated modelling of the lithosphere which combines the interpretation of surface heat flow, geoid, gravity, and topography data in the Carpathian–Pannonian Basin region and surrounding areas. This approach is able to constrain the complicated lithospheric structures of the studied region better than interpreting each data set onits own. We present four 2D integrated models of the lithosphere in the Carpathian–PannonianBasin region and surrounding areas. Finally, based on the 3D Inversion algorithm, we present the geophysical models of the lithosphere in the Carpathian–Pannonian region. The algorithm returns the density structure of the lithosphere from joint inversion of free air gravity, geoid andtopography data based on a Bayesian approach. The models are based on different input data sets and constrained by different a priori data. Based on our modelling we cannot confirm theextreme thinning (less than 70 km) of the Pannonian Basin lithosphere proposed by other authors.On the other hand, the results show the increasing trend of the lithospherical thickness of theCarpathian Arc from the Western Carpathians toward the Eastern Carpathians which confirms theprevious theories about the propagation of subduction process. We got some controversial resultsin the area of the Southern Carpathians. The results based on 3D inversion show extremely thinlithosphere in the area; on the other hand, the results based on 2D integrated modelling do notsupport such thinning. However both methods indicate that it is probable that the MoesianPlatform is bend and underthrusted underneath the Southern Carpathians. The south-eastern edge of the Pannonian Basin based on 3D inversion shows unexpected and surprisingly thinlithosphere. Since the area is quite large, we could exclude an effect of flexure, therefore this area might be potentially interesting for further investigation. / Hlavnou myšlienkou tejto práce bolo rozšírenie poznatkov o štruktúre a tektonike karpatsko–panónskej oblasti. Na výskum študovanej oblasti sme použili tri rôzne metódy, 1D automatickémodelovanie, 2D integrované geofyzikálne modelovanie a 3D inverziu. Tieto metódy sú podobnév zmysle použitých vstupných databáz, ale líšia sa spôsobom spracovania a interpretácie. Akoprvé sme aplikovali 1D automatické modelovanie, ktoré slúžilo ako prvý náhľad na študovanéúzemie. Ako druhé sme použili 2D integrované geofyzikálne modelovanie litosféry, ktorékombinuje interpretáciu povrchového toku, geoidu, tiažových anomálií a topografie v karpatsko–panónskej oblasti a okolitých tektonických jednotkách. Tento prístup k interpretácii je schopnývymedziť komplikované štrúktúry v litosfére lepšie, ako interpretácia každého jednéhogeofyzikálneho poľa samostatne. V tejto práci predstavíme štyri 2D integrované modely litosféryv karpatsko–panónskej oblasti a okolitých jednotiek. Ako posledné, predstavíme geofyzikálnemodely litosféry študovanej oblasti na základe modelovania použitím 3D inverzie. Algoritmus jeschopný vypočítať hustotnú distribúciu v litosfére na základe Bayesianského prístupu zospoločnej inverzie tiažovej anomálie na voľný vzduch, geoidu a topografie. Tieto modely súvypočítavané na základe rôznych vstupných datových setov a a priori informácií. Na základenášho modelovania nemôžeme potvrdiť extrémne stenčenie (menej ako 70 km) litosférypanónskej panvy. Na druhej strane naše výsledky poukazujú na narastajúci trend litosférickéhohrubnutia Karpatského oblúka od Západných Karpát smerom do Východných, čo potvrdzujepredchádzajúce teórie o postupnom procese subdukcie. V oblasti Južných Karpát sme dosiahliprotichodné výsledky. Výsledky získané na základe 3D inverzie poukazujú na extrémne stenčenúlitosféru na druhej strane 2D integrované modelovania takéto extrémne stenčenie v danej oblastinepodporuje. Napriek tomu je pravdepodobnejšie, že moezíjska platforma je ohnutá a podsunutápod Južné Karpaty. Ďalšia zaujímavá vec sa ukazuje v juhovýchodnej oblasti panónskej panvy,kde výsledky 3D inverzie odhaľujú taktiež výrazné stenčenie litosféry. Táto oblasť môže byťpotenciálne zaujímavá a bolo by vhodné ďalej pokračovať vo výskume danej oblasti.
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Modèle effectif par une approche de Saint-Venant pour les écoulements complexes lors d'inondations urbaines / Effective shallow water models for complex flood flow patterns in urban areasChen, Shangzhi 04 June 2018 (has links)
Les inondations représentent le premier danger naturel sur chaque continent, avec des préoccupations particulières centrées sur les inondations urbaines pour l'urbanisation sans précédent, qui augmente la vulnérabilité des sociétés humaines aux inondations. Pour les difficultés d'accès aux données en temps réel, la méthode numérique semble être une approche puissante pour la prévision des inondations et l'atténuation des dommages. Dans cette thèse, un nouveau logiciel Flood1D2D pour la modélisation des crues urbaines a été proposé en utilisant le maillage de couplage 1D2D, avec 1D dans la rue et 2D appliqué au carrefour. Le logiciel est conçu sur la base de l'installation située dans ICube Strasbourg et validée à l'aide de cas de tests synthétiques. La nouveauté du modèle est de rendre compte de l'effet de recirculation en utilisant la fonction de porosité, et de reproduire la convexité dans les profils de profondeur le long de la rue en aval de chaque carrefour où une zone de recirculation apparaît. Une analyse de sensibilité basée sur la variance est également réalisée pour les modèles classiques d'eau peu profonde 1D et 2D pour l'étalonnage de modèles et la collecte de données. / Flooding represents the first natural hazard on each continent, with special concerns are focused on urban flooding for the unprecedented urbanization, which increases the vulnerability of human societies to floods. For the accessing difficulties of real-time data, numerical method seems to be a powerful approach for flood forecasting and damage mitigation. In this thesis, a new software Flood1D2D for urban flood modeling has been proposed using 1D2D coupling mesh, with 1D on the street and 2D applied on the crossroad. The software is designed based on the rig located in ICube Strasbourg and validated using synthetic test cases. The novelty of the model is to account for the recirculation effect using porosity function, and it can reproduce the convexity in water depth profiles along the street downstream each crossroad where a recirculation zone appears, which can't be accounted using roughness only. Variance based sensitivity analysis is also performed for classical 1D and 2D shallow water models for model calibration and data collections.
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Hydrodynamický model Svitavy a Svratky na území města Brna / Hydrodynamic model of the Svitava and Svratka rivers in BrnoRačoch, Tomáš January 2019 (has links)
The Master‘s thesis deals with the assessment of the current state of flood protection in the rivers and floodplains of Svitava (km 0.000 - 2,050) and Svratka (km 26,370 - 33,963) in Brno. Using a combined 1D and 2D numerical model of water flow, hydraulic calculations of the peak flows of Q5, Q20 and Q100 were performed. For calculation, HEC-RAS 5.0.6 was used. The outputs were processed in the form of flood hazard maps and drawing documentation.
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Hydraulické posouzení vlivu revitalizace vodního toku na retenční kapacitu údolní nivy / Hydraulic assessment of a stream revitalization effect on a floodplain retention capacityBerka, Ondřej January 2015 (has links)
Diploma thesis “Hydraulic Assessment of a Stream Revitalization Effect on a Floodplain Retention Capacity“ assess availability of revitalized stream and its floodplain to transform floods and compare determined values with transformed floods from model of technically modified stream, both by using coupling 1D/2D BASEMENT computational model. In the first part is overall introduction to research issue. In the second part the territory of interest is described and the hypothesis are set. In the third part are described input data, used tools, computational model, its making and computational versions. In the fourth part the hypothesis are evaluated. It was determined, that for in this thesis used terrain and hydrographs are floods smaller than Q20 transformed much more by revitalized stream and that technically modified stream can speed up the flood, floods Q50 and Q100 are more transformed by technically modified stream. For generalization of the results would be appropriate to make research on bigger ammount of case studies based on combination of 1D/2D and rainfall-runoff model.
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Interaction and mixing effects in two and one dimensional hole systemsDaneshvar, Ahrash January 2008 (has links)
This thesis describes electrical measurements performed on low dimensional p-type devices, fabricated from GaAs/AlGaAs heterostructures. The Coulomb interaction between holes is similar to that between electrons. However, the kinetic energy is suppressed, which makes interaction effects particularly important. Holes may also be used to study band structure effects which arise from spin-orbit coupling in the valence band. The effects of Coulomb interactions in low dimensional electron systems are currently being studied extensively. Experiments presented in this thesis indicate the possible importance of Coulomb exchange interactions in both one and two dimensional hole systems (1DHSs,2DHSs). Tilted magnetic field studies of 2DHSs in the quantum Hall regime indicate that Landau levels at even filling factors will not cross. For high filling factor, this is attributed to a spin-orbit mixing effect which arises from the low symmetry ofthe system. At lower filling factor, activation-energy measurements verify that the energy gaps decrease and then increase as the field is tilted. However, the energy gap versus field dependences do not exhibit the curvature that might be expected from a perturbative anticrossing. It is speculated that the origin of this effect is a phase transition driven by the exchange interaction. Balanced arguments contrasting the relative strengths of the mixing and interactions theories are provided. The second part of this thesis describes a new method for the fabrication ofballistic 1DHSs, which exhibit clear conductance quantization. The quantization changes from even to odd multiples of e2/h as a function of the magnetic field in the plane of the heterostructure, as 'spin splitting' causes the 1D subbands to cross. Measurements of the 1D subband energy spacings are used together with the magnetic fields at which the crossings occur to calculate the in-plane g factors of the 1D subbands. These are found to increase as the number of occupied 1D subbands decreases. This enhancement of the g factor is attributed to exchange interactions; possible mixing explanations are also discussed. At higher magnetic fields, the pattern of quantization features shows that the subbands have crossed many times, and that the 1DHS can be strongly magnetized.
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Performance and uncertainty estimation of 1- and 2-dimensional flood modelsLim, Nancy Joy January 2011 (has links)
Performance-based measures are used to validate and quantify how likely the system’s results resemble that of the actual data. Its application in inundation studies is performed by comparing the extents of the predicted flood to the real event by measuring their overlap size and getting the percentage of this size to the union of both data. In this study, performances of 1- and 2-dimensional flow models were assessed when used with different topographic data sources, rasterisation cell sizes, mesh resolution and Manning’s values with the help of Geographic Information Systems (GIS). The Generalised Likelihood Uncertainty Estimation (GLUE) was also implemented to evaluate the behaviour and the uncertainties of the Hydrologic Engineering Center-River Analysis System (HEC-RAS) steady-flow model in delineating the inundation extents when various sets of friction coefficients for floodplain and channel were utilised as inputs. Although it was not possible to perform the GLUE procedure with Telemac-2D due to the simulation time, Manning’s n performances’ effects were evaluated using ten randomly selected sets of friction for the channel and floodplain. The LiDAR data, which had the highest resolution, performed well in all simulations, followed by Lantmäteriet data at 50 m resolution. The lowest resolution Digital Terrain Elevation Data (DTED) showed poor resemblance to the actual event and big misrepresentations of flooded areas. Rasterisation cell sizes in HEC-RAS showed minimal effect to the inundation limits when used between 1 m and 5 m, but performance started to deteriorate at 10 m (Lantmäteriet) and 20 m (LiDAR). The 10 m mesh resolution used for LiDAR behaved poorer than the 20 m mesh, which performed well in the different 2D simulations. For HEC-RAS, =0.033 to 0.05 performed well when paired with =0.02 to 0.10. It was apparent, therefore, that the channel’s Manning’s n affected the performances of the floodplain’s . Furthermore, the study also showed that using heterogeneous roughness values corresponding to the different land use classes is not as effective as using single channel and floodplain’s Manning. The dependence of the floodplain’s roughness to the channel’s friction values had also been manifested by Telemac, even though it required lower values than the 1D simulator. = 0.007 to 0.019 and =0.01 to 0.04 gave good performance to the 2D system. In terms of the overall model performance, HEC-RAS 1D exhibited good results for Testeboån. Even when the average distances to the actual data were estimated, the breadths were shorter compared to the most optimal output of the two-dimensional simulator, which showed more overestimated areas, despite the fact that the overlap size with the 1977 actual event was better than HEC-RAS. It could be because the measures-of-fit took into consideration the areal sizes that were over- and under-predicted aside from the overlap sizes between the observed and modelled results. This could be the same reason with the mean distances produced, wherein higher values were computed for Telemac-2D due to its bigger gap from the actual flood as brought by the enlargement in the flood extents. But it was also made known in the study that such ambiguities in the model performance were further contributed by the characteristics of the floodplain’s topography of being flat. Testeboån’s inclination to the banks was averaged at 0.027 m/m, with the central portion at 0.002 m/m. The middle portion of the floodplain was illustrated to contain more uncertain regions, where water extents changed easily as the parameters were altered. Distances greater than 200 m were also mostly located within these inclination values or within 0.005 to 0.006 m/m. The response of distance to the floodplain’s gradient improved when the slope value became higher, and this had been particularly noticed between 0 to 50 m.
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Skyfallsanalys i urban miljö : En komparativ studie mellan MIKE 21 och MIKE FLOOD / Flood modelling in urban areas : A comparative study of MIKE 21 and MIKE FLOODAndersson, Elin January 2020 (has links)
Redan idag har många kommuner i Sverige drabbats av skyfall och ett förändrande klimat indikerar att skyfall kommer bli vanligare. Översvämningar till följd av skyfall kan ge konsekvenser som skador på hus, vägar och även utgöra fara för människors hälsa. Skyfallskartering är ett verktyg som kan användas för att identifiera utsatta områden vid inträffandet av ett extremt regnförlopp. DHI har utvecklat MIKE 21 och MIKE Flood som kan användas vid skyfallsmodellering. MIKE Flood är en kopplad 1D-2D modell där ledningsnätet integreras. MIKE 21 är en 2D modell där regnets transportväg på ytan simuleras, ledningsnätet representeras av ett schablonvärde som dras bort från regnet som belastar modellen. Denna studie avser att jämföra dessa modeller för att undersöka behovet av att integrera ledningsnätet, samt utreda hur olika belastningar på ledningsnätet påverkar resultatet. Denna komparativa studie bygger på att MIKE 21 och MIKE Flood sätts upp för samma område lokaliserat i Nacka. Modelleringen resulterar i en karta som visar vattendjup och översvämningens utbredning. Resultatet visar att den största differensen mellan vattendjupen uppstår för djup mellan 0.1 till 0.3 meter. Vidare ger MIKE Flood generellt en större översvämningsutbredning än MIKE 21. Anledningen till denna skillnad är interaktionen mellan 1D och 2D modellen i MIKE Flood. Valet av schablonvärde är viktigt för MIKE 21 modellen då det har en stor påverkan på översvämningsutbredningen. Ledningsnätet betydelse minskar desto mer extrem nederbörden är. / Several municipalities in Sweden have been affected by cloudbursts and a changing climate indicates a future where these events gets more common. Cloudburst are events where extreme precipitation takes place under a short period of time. The consequences is flooding where damages to property and impede accessibility for emergency vehicles are some possible effects. Flood modelling is a way to identify vulnerable areas so that mitigations can be implemented. For example municipalities can use it when planning for new household areas and infrastructure. The Danish Hydrological Institute (DHI) has developed MIKE 21 and MIKE Flood. MIKE Flood is a coupled 1D-2D model while MIKE 21 is a 2D model. For the coupled model the storm water collection system can be integrated and represented by the model MIKE Urban. In the MIKE 21 model the collection system is represented by withdrawing a standard value from the applied rainfall. This comes with the assumption that the collection system fills up completely with the assumed capacity represented by the standard value. Since, MIKE Flood is a coupled 1D-2D model it requires more time and data to set up than the 2D model. Therefore, this study aims to compare these models in order to evaluate the impact of implementing the storm water collection system. Further, to evaluate how the division of the rain loads to each model affect the modelling results. This thesis is performed by setting up MIKE 21 and MIKE Flood for an area in Nacka. The models will be run for six scenarios, which results in a total of 12 simulations. For the scenarios two different recurrences are tested, a 100 and 50 year cloudburst event. Further, the collection system is represented with three different loads corresponding to a 5, 10 or 20 year rainfall event. The modelling results in maps containing water depths and flood extent. In order to compare the models the generated water depths and extent was compared. If the difference between the models was lower than 0.1 meter they was assumed to generate approximately the same result. In order to examine how well MIKE 21 and MIKE Flood matched in the different scenarios an index, measure of fit, was calculated. Moreover, the interaction between the 1D and 2D model was investigated for MIKE Flood. The result showed that there was a difference in flood depth and extent between MIKE 21 and MIKE Flood. Generally there were more flooded cells in MIKE Flood than in MIKE 21 for each scenario besides one. The larges difference between generated water depths was for depths between 0.1 to 0.3 meters. MIKE flood generates a bigger flood extent downstream along the collection system due to the lack of capacity in those parts of the collection system, along Vikdalsvägen the collection system seem to have the capacity to handle a 5 year load. The probable reason for the difference is the interaction between the collection system and 2D model. The collection system, MIKE Urban, enters new paths for the rain to travel that is not available in a 2D model. In areas where the capacity is reached there will be a flux from the 1D model to the 2D model and in areas whit capacity the flux can be in the opposite direction. The assumption that the collection system fills up entirely is not correct for Nacka. Further, the difference between the results from MIKE 21 and MIKE Flood increased with a higher network load. Which indicates that the importance of the storm water collection system reduces with more extreme precipitation events. That is the reason the index, measure of fit, is higher for the scenarios with a cloudburst of a 100 year return period.
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