The thesis deals with silting of water reservoir Nové Heřminovy. There's describe design of artificial traffic and evaluate its effectiveness. To determine the flow of sediment into the reservoir with use a partially calibrated one-dimensional numerical model of sediment transport with deformation of bed is made in software HEC-RAS. Silting reservoirs is assessment with two methods, the results are compared and describes their limitations. Reservoirs silting evaluates through volume changes in reservoir storage in time.

The thesis deals the assessment of the resistance of the existing boulder chute in the river Lomná. At km 1,9 Boulder chute is located in the village Jablunkov. Surface resistance of boulder chute is assessed newly on the basis of non-dimensional shear stress for particle on arbitrarily sloped bed. The calculation of 2D flow was computed by HEC-RAS. On the assessment of resistance was proposed reconstruction of boulder chute.

Background Controlled mechanical ventilation with randomly variable tidal volume patterns has been shown to improve gas exchange and respiratory system mechanics compared to conventional ventilation in numerous experimental models of acute respiratory distress syndrome (ARDS). Multiple mechanisms have been proposed to explain this phenomenon called stochastic resonance. The recruitment of collapsed lung regions has been proposed as the dominant mechanism, but the role of respiratory system recruitment and de-recruitment dynamics during variable ventilation and the influence of periodic instead of random variation has not been elucidated. Objectives The primary objective of this thesis was to investigate the effects of periodic tidal volume patterns during variable ventilation on functional parameters with a special focus on gas exchange, respiratory system mechanics and cardiovascular interactions. Further aims were to elucidate the relationship between recruitment and de-recruitment dynamics and recruitment effects of random variable ventilation as well as the impact of an excessive increase in pattern period during variable ventilation on respiratory system mechanics. Finally, the relationship between recruitment effects during variable ventilation and the recruitment and de-recruitment dynamics as well as the ability of random variable ventilation to prevent de-recruitment are to be clarified. Methods Recruitment and de-recruitment dynamics were investigated based on the analysis of the time course of dynamic respiratory system elastance in a double-hit model of ARDS in pigs, a model of lung inflammation in rats, and in silico. The effects of periodic variable ventilation were studied for a wide range of pattern periods using a non-linear computational model of respiratory system mechanics, and in two experimental studies: Partial pressure of oxygen in arterial blood (PaO2) was the primary outcome of the longitudinal study during six hours of therapy in a double-hit model of ARDS in pigs. A cross-over study in a hydrochloric acid-induced model of ARDS in rats was performed to investigate the effects of periodic variable ventilation on baroreflex and respiratory sinus arrhythmia in context of the improvement of the primary end-point PaO2. In both studies, tidal volume patterns were chosen to have main periods overlapping with the dynamics of cardiovascular and respiratory sub-systems. Results and Discussion Periodic variable ventilation, but not random variable ventilation, improved PaO2 compared to conventional ventilation in the double hit model of ARDS. In both experimental studies, variable ventilation independent of pattern period improved respiratory system elastance. The study in silico indicated that periodic patterns have no additional positive effect on respiratory system mechanics compared to random patterns, but will attenuate recruitment for an excessive increase in pattern period. Baroreflex and respiratory sinus arrhythmia were affected by periodic tidal volume patterns in the acid-induced ARDS model; however, pattern period was associated with a decrease in PaO2. Recruitment and de-recruitment dynamics in the experimental model were similar to values derived by analysis of dynamic computed tomography according to literature. In the computational study, re-cruitment during random variable ventilation was maximised for specific values of recruitment and de-recruitment dynamics. Recruitment dynamics were lower during random variable ventilation compared to conventional recruitment manoeuvres, however in the range of de-recruitment dynamics of the respective model. Consequently, random variable ventilation with a coefficient of variation of 30 % was sufficient to prevent an increase of respiratory system elastance during ventilation in the study on acute lung inflammation in rats. Conclusion The asymmetry between recruitment and de-recruitment dynamics, which could be quantified by the analysis of the time course of dynamic elastance, was associated with recruitment during random variable ventilation in numerical simulations. Periodic variable ventilation improved arterial oxygenation to a clinically relevant extent without concomitant improvement of lung recruitment compared to random variable ventilation in a double-hit model of ARDS. Cardiovascular-respiratory interactions and asymmetry of recruitment and de-recruitment dynamics were not associated with this improvement. / Hintergrund In zahlreichen experimentellen Modellen des Akuten Atemnotsyndroms (ARDS) konnte gezeigt werden, dass die kontrollierte maschinelle Beatmung mit zufällig variablen Tidalvolumen pro Atemzug den Gasaustausch und die Atemmechanik im Vergleich zur konventionellen maschinellen Beatmung deutlich verbessert. Es wurden mehrere Mechanismen zur Erklärung dieses Phänomens, der Stochastischen Resonanz, vorgeschlagen. Die Wiedereröffnung kollabierter Lungenareale (Rekrutierung) ist dabei als dominanter Mechanismus der variablen Beatmung identifiziert wurden. Die Rolle der Dynamik von Rekrutierung und Derekrutierung sowie der Einfluss von Periodizität an Stelle von Zufälligkeit in der Sequenz der Tidalvolumina während Zufälliger Variabler Maschineller Beatmung (ZVB) wurde bisher lediglich in numerischen Simulationen evaluiert. Fragestellung Hauptziel dieser Arbeit war es, die Auswirkungen der Periodischen Variablen Maschinellen Beatmung (PVB) auf Gasaustausch, Mechanik des Respiratorischen Systems sowie Kardiovaskulärer Wechselwirkungen zu untersuchen. Ferner sollten mögliche Mechanismen der PVB identifiziert werden. Der Zusammenhang zwischen der Rekrutierungsdynamik und den Rekrutierungseffekten der ZVB sowie den Auswirkungen einer übermäßigen Erhöhung der Periodendauer während der PVB auf die Mechanik des Respiratorischen System war ebenfalls zu untersuchen. Ferner war der Zusammenhang zwischen den Rekrutierungseffekten bei der ZVB und der Dynamik der Rekrutierung / Derekrutierung des Respiratorischen Systems zu untersuchen. Material und Methoden In einem nichtlinearen numerischen Modell der Atemmechanik wurden die Auswirkungen der PVB für einen breiten Bereich von Periodendauern untersucht. Die Dynamik der Rekrutierung und Derekrutierung der Lunge wurde basierend auf der Analyse des Zeitverlaufs der dynamischen Elastance des Respiratorischen Systems in einem Doppelhit-Modell des ARDS im Schwein, einem Modell der Lungenentzündung in der Ratte sowie in silico untersucht. Die Effekte der PVB auf Gasaustausch und Atemmechanik wurden in zwei experimentelle Studien in verschiedenen Modellen des experimentellen ARDS untersucht: Der Partialdruck von Sauerstoff im arteriellen Blut (PaO2 ) war die primäre Zielgröße in der Längsschnittuntersuchung während der sechsstündigen Therapie des experimentellen ARDS am Hausschwein, welches induziert wurde durch wiederholte Auswaschung von Surfaktant mit anschließender beatmungsinduzierter Lungenschädigung. In einer Cross-over-Studie an einem salzsäureinduzierten Modell des ARDS in Ratten wurden die Auswirkungen der PVB auf Baroreflex- und respiratorische Sinusarrhythmie im Zusammenhang mit dem primären Endpunkt PaO2 untersucht. Ergebnisse und Diskussion PVB jedoch nicht die ZVB, verbesserte den PaO2 im Vergleich zur konventionellen maschinellen Beatmung im Doppelhit-Modell des ARDS während sechstündiger Therapie. In beiden Studien verbesserte die PVB unabhängig von der Periodendauer die Elastance des Respiratorischen Systems. Die Simulationen am Computermodell bestätigten, dass periodische Muster keinen zusätzlichen positiven Effekt auf die Mechanik des Atmungssystems im Vergleich zu zufälligen Mustern haben, aber die Rekrutierung während Variabler Maschineller Beatmung für eine übermäßige Erhöhung der Periodendauer abschwächen können. Baroreflex und Respiratorische Sinusarrhythmie wurden durch periodische Sequenz aufeinander folgender Tidalvolumina im säure-induzierten ARDS-Modell beeinflusst, jedoch war die Musterperiode mit einem Rückgang des PaO2 assoziiert. Die im experimentellen Modell bestimmte Dynamik der Rekrutierung und Derekrutierung bestätigte aus der Literatur bekannte Werte, die durch die Analyse der dynamischen Computertomographie gewonnen wurden. In der numerischen Modell-Studie zeigte sich, dass die Rekrutierung während der ZVB für bestimmte Verhältnisse zwischen Rekrutierungs- und Derekrutierungsdynamik (Asymmetrie) maximiert werden. Die Dynamik der Rekrutierung war bei der ZVB im Vergleich zu herkömmlichen Rekrutierungsmanövern geringer, jedoch innerhalb des Wertebereichs der Dynamik der Rekrutierung des jeweiligen Modells. Folglich konnte durch ZVB mit einem Variationskoeffizienten von 30 % die Derekru- tierung der Lunge in einem Modell der akuten Lungenentzündung verhindert werden. Schlussfolgerung Die Asymmetrie zwischen der Dynamik der Rekrutierung und Derekrutierung der Lunge, die durch die Analyse des Zeitverlaufs der dynamischen Elastance quantifiziert werden konnte, war mit der Rekrutierung während der Zufälligen Variablen Beatmung in numerischen Simulationen assoziiert. Die Periodisch Variable Beatmung verbesserte die arterielle Oxygenierung in einem klinisch relevanten Umfang ohne gleichzeitige Verbesserung der Lungenrekrutierung im Vergleich zur Zufälligen Variablen Beatmung in einem Doppelhit-Modell des ARDS am Schwein. Weder Kardiovaskulär-respiratorische Wechselwirkungen noch die Asymmetrien der Rekrutierungs- und Derekruitierungsdynamik standen mit dieser Verbesserung im Zusammenhang.

Recently observed cumulation of unexpected collapses of slope-distant waste dumps in lignite mining areas of eastern germany re-initiated research of soil liquefaction. Especially it turned the question of internal initials that correspond to water rise. Parallel to laboritory tests and field experiments a micromechanical model should be developed, which can reproduce processes in the soil during saturation. In first approximation a partly saturated soil consists of two phases: the soil particles and the pore fluid. For micromechanical modeling a coupling of discontinuum particles) and continuum (fluid) is required. The soil particles can be simulated with the Discrete-Element-Method (DEM). For the pore fluid, which is assumed to be a mixture of liquid and gaseous fractions, Pore scale model with Finite Volumes (PFV) is used. At low water content liquid bridges (meniscii) arise between the particles that cause an apparent cohesion. The effect of the meniscii is considered by a correspondingly contact law in the DEM model. During the saturation of a soil both, cohesive effect and fluid bulk modulus, are reduced. In addition buoyancy acts on the particles during the process. The micromechanical modeling approach has the advantage, that just a few model parameters are needed. The numerical model shows pore fluid pressures during saturation process, that leads to a reduction of effective stress. It is investigated how much the reduction is regarding porosity, degree of saturation, stress conditions and grain shape. Furthermore the influence of model parameters as well as hydromechanics is investigated. The investigations are completed with another series of experiments under special conditions like integration of macropores, horizontal fixed model boundaries and abrupt saturation.:Einleitung Literaturauswertung Numerische Modellierung Modellstudien Ergebnisauswertung Zusammenfassung Extended summary

The construction industry is moving towards an increasingly industrial production and one step towards this is to use prefabricated rebar cages. A new concept is being tested where tied rebar cages are produced on the construction site by industrial robots. The industrial robots produce the rebar cages based on a geometric model and when finished they are lifted to the casting site with the help of a crane. In order for this concept to become an efficient process, it must already be possible to evaluate the stability of the rebar cages in the early design phase to be able to efficiently determine whether it is possible to lift the rebar cages to the casting site after production. The scope of this thesis is to investigate what is required to create a numerical model with help of data from a geometric model in an efficient way in order to determine whether a rebar cage can be lifted. This thesis is limited to one specific rebar cage that has already been created in the CADprogram Tekla Structures by the contractor Skanska Sweden AB. The process of what is required when creating a numerical model with data from a geometric model is limited between the analysis software LUSAS Bridge and the CAD software Tekla Structures. To be able to determine what is required in order to create a numerical model with data from a geometric model in the analysis software LUSAS Bridge in an efficient way a survey was performed. The survey includes the necessary steps to create a numerical model of a tied rebar cage from a geometric model and the problems that occurs along the way to get an efficient process. In order to determine if the geometric model of the rebar cage is liftable a linear analysis was created in the analysis software LUSAS Bridge. The analysis was created with data from the geometric model created in Tekla Structures and with experimental results from a study where tied connection strength and stiffness were evaluated. The analysis was created to simulate a rebar cage for a bridge foundation in scale 1:2 that is lifted in four lifting points. The lifting points in this analysis is modeled as supports while the rebar cage is subjected to an acceleration force to simulate a lift. The analysis is performed in two parts, first when the tied connections have full stiffness capacity and the second part when the stiffness is decreased to be able to evaluate what happens to the stability of the rebar cage. In order to determine if the rebar cage is liftable two conditions are looked at, (1) stress in rebars and (2) forces in the joint elements. The results from the study show that in order to create a numerical model of a tied rebar cage in an efficient way some improvements must be done in the analysis software LUSAS Bridge. The most time-consuming process when creating a numerical model of a tied rebar cage are the connections. In order to create these tied connections in an efficient way some new functions must be created in LUSAS Bridge where the software can generate different types of tied connections. The results from the analysis show that the stress in the rebars at the lifting points is the criterion that is most critical when the rebar cage is lifted. The maximum stress reached 356 MPa with the utilization rate of 81,9% when the connection stiffness has full capacity. When the connection stiffness was adjusted, it was also shown here that the stress was the criterion that is most critical. The analysis for 50% connection stiffness capacity showed a maximum stress of 402 MPa with the utilization rate of 92,4%, this shows an increase of 10,5% of the utilization rate when the IV  connection stiffness is decreased with 50%. Based on these results, it can be stated that the rebar cage can be lifted if four lifting points are used. It can also be seen from the results that the stiffness in the connections has a very small impact on the behavior of the cage and therefore the placement of the rebars contributes more to the stability. / Byggindustrin går mot ett allt mer industriellt byggande och ett steg på vägen är att använda sig av prefabricerade armeringskorgar. Ett nytt koncept håller på att undersökas där man vill framställa najade armeringskorgar på byggarbetsplatsen med hjälp av industrirobotar. Industrirobotarna bygger armeringskorgarna utifrån en geometrisk modell för att sedan lyftas till gjutplatsen med hjälp av en kran. För att detta koncept ska bli en effektiv process måste man redan i projekteringsfasen kunna utvärdera armeringskorgarnas lyftbarhet för att kunna avgöra om det går att lyfta armeringskorgarna till gjutplatsen efter att de är färdigmonterade. Examensarbetets syfte är att undersöka vad som krävs för att ska skapa en numerisk modell med hjälp av data från en geometrisk modell på ett effektivt sätt för att sedan kunna avgöra om en armeringskorg går att lyfta. Denna studie är avgränsad till enbart en typ av armeringskorg som redan är skapad i CADprogrammet Tekla Structures av entreprenören Skanska Sverige AB. Processen som krävs för att skapa en numerisk modell med hjälp av en geometrisk modell är begränsad till analysprogrammet LUSAS Bridge och CAD-programmet Tekla Structures. För att kunna avgöra vad som krävs för att skapa en numerisk modell med hjälp av en geometrisk modell i analysprogrammet LUSAS Bridge utfördes en kartläggning. Kartläggningen omfattar de steg som krävs för att skapa en numerisk modell av en najad armeringskorg från en geometrisk modell och de svårigheter som finns längs vägen. För att kunna avgöra om den geometriska modellen av armeringskorgen är lyftbar skapades en linjär Finita Element Analys i analysprogrammet LUSAS Bridge. Analysen är skapad med hjälp av data från den geometriska modellen från Tekla Structures samt testresultat från en tidigare studie där man har provat hållfastheten och styvheten hos najade knutpunkter. Analysen är skapad för att efterlikna en armeringskorg till ett brofundament i skala 1:2 som lyfts i fyra punkter. Lyftpunkterna i denna analys är simulerade som stöd medan armeringskorgen utsätts för en accelerationskraft för att efterlikna ett lyft. Analysen utförs i två delar, en när de najade knutpunkterna har full styvhet och den andra när styvhet för knutpunkterna minskar. Detta för att se hur styvheten i knutpunkterna påverkar stabiliteten i armeringskorgen. Armeringskorgens lyftbarhet bedöms av två olika kriterier (1) spänning i armeringsjärnen och (2) krafter i knutpunkterna. Resultaten från studien visar att för att kunna skapa en numeriskmodell av en najad armeringskorg på ett effektivt sätt måste en del förbättringar göras i analysprogrammet LUSAS Bridge. Den process som är mest tidskrävande är när man skapar de najade knutpunkterna för armeringskorgen. För att det ska gå att genomföra detta på ett effektivt sätt måste en ny funktion skapas i LUSAS Bridge där programmet kan generera olika typer av knutpunkter automatiskt. Resultaten från analysen visade att spänningen av armeringsjärnen vid lyftpunkterna är det kriterium som är mest kritisk när armeringskorgen utsätts för lyft. Den maximala spänningen uppgick till 356 MPa med en utnyttjandegrad på 81,9% för armeringskorgen med full styvhet. När styvheten justerades visades det även här att spänningen är det kriterium som är mest kritiskt. Analysen för 50% styvhet visade en maximal spänning på 402 MPa med en utnyttjande grad på 92,4%, detta visar en ökning på 10,5% av utnyttjandegraden när styvheten halveras. VI  Utifrån dessa resultat kan man konstatera att armeringskorgen går att lyfta om man använder fyra lyftpunkter. Man kan även utifrån resultaten se att en minskning av styvheten i knutpunkterna har en liten påverkar på armeringskorgens lyftbarhet och istället är det placeringen av armeringsjärnen som har störst betydelse.

Diploma thesis deals with the issue of terrrorism in relation to soft targets and subsequent assessment of the selected soft target in terms of possible terrorist attack. The objective is primary school Sirotkova in Brno. The assessment criteria was evacuation of the school as a whole and its individual parts. A risk analysis was performed for the object to determine real threats in which there were clasified the probability and extent of impacts of potential attacks. The most likely scenarios of the attack were identified, based on this analysis. These scenarios were subsequently implemented into an advanced numerical 3D model, where the evacuation was simulated within these scenarios. In the framework of the school assessment, the work focused on comparing three different approaches to the evacuation process. The evacuation process was compared according to parameters of experimental data obtained from the practise of evacuation of primary school with evacuation processes set acording to the parameters of fire standards CSN and international SFPE fire safety standards. The results of the individual simulations were processed with a statistically determined probability percentile. The outcome of the assessment was to determine the probable evacuation time of the school and its individual parts. Based on these results, there was performed a proposal to optimize the evacuation process of the school, which made the process more efective and shortened the evacuation time to minimalize the impact of a potential terrorist attack.

Continuous casting is a dominant production technology of steelmaking which is currently used for more that 95% of the world steel production. Mathematical modelling and optimal control of casting machine are crucial tasks in continuous steel casting which directly influence productivity and quality of produced steel, competitiveness of steelworks, safety of casting machine operation and its impact on the environment. This thesis concerns with the development and implementation of the numerical model of temperature field for continuously cast steel billets and its use for optimal control of the casting machine. The numerical model was developed and implemented in MATLAB. Due to computational demands the model was parallelized by means of the computation on graphics processing units NVIDIA with the computational architecture CUDA. Validation and verification of the model were performed with the use of operational data from Trinecke zelezarny steelworks. The model was then utilized as a part of the developed model-based predictive control system for the optimal control of dynamic situations in the casting machine operation. The behaviour of the developed control system was examined by means of dynamic model situations that have confirmed the ability of the implemented system to optimally control dynamic operations of the continuous casting machine. Both the numerical model of the temperature field and the model-based predictive control system have been implemented so that they can be modified for any casting machine and this allows for their prospective commercial applications.

The subject of the submitted work is the experimental and theoretical investigation of composite slabs. The work also deals with creation of numerical models of composite slabs. The design of a new type of steel sheeting for composite slab according to nowadays standards requires full scale laboratory bending tests. An alternative to the bending tests are the small scale shear tests. The small scale shear tests as well as corresponding design methods have already been investigated by many researchers. Therefore several test arrangements and corresponding design methods can be found in literature but none of them is included in standards yet. The submitted thesis describes three of the alternative design methods: Slip- Block Test, Simplified Method and Built-up Bars. The test arrangement is proposed to be usable in all these methods. The small scale shear test have been performed in laboratory in several modifications. The results were used to calculate the bending resistance of the slab by the alternative design methods. The calculated bending resistances were mutually compared, compared with the performed bending tests resistances and the resistances by the methods described in Eurocode: m-k method and partial connection method. A sensitivity studies of the input parameters in alternative design methods are presented as well. The optimal design method for use in practice was searched and recommended based on the performed studies, accuracy and laboriousness of the methods. The shear tests were used also to measure longitudinal shear resistance of the additional shear anchors. The alternative design methods were used to predict bending resistance of the slab using these anchors and the results were compared. The numerical simulation of the composite action of the slab by the finite element methods is modelled in Atena software. The models serves to perform parametrical studies and to better understand of the behaviour of the slab in partial composite action.

A research study has been conducted to simulate liquefaction in saturated sandy soil induced by nearby controlled blasts. The purpose of the study is to help quantify soil characteristics under multiple and consecutive high-magnitude shock environments similar to those produced by large earthquakes. The simulation procedure involved the modeling of a three-dimensional half-space soil region with pre-defined, embedded, and strategically located explosive charges to be detonated at specific time intervals. LS-DYNA, a commercially available finite element hydrocode, was the solver used to simulate the event. A new geo-material model developed under the direction of the U.S. Federal Highway Administration was applied to evaluate the liquefaction potential of saturated sandy soil subjected to sequential blast environments. Additional procedural enhancements were integrated into the analysis process to represent volumetric effects of the saturated soil's transition from solid to liquid during the liquefaction process. Explosive charge detonation and pressure development characteristics were modeled using proven and accepted modeling techniques. As explosive charges were detonated in a pre-defined order, development of pore water pressure, volumetric (compressive) strains, shear strains, and particle accelerations were carefully computed and monitored using custom developed MathCad and C/C++ routines. Results of the study were compared against blast-test data gathered at the Fraser River Delta region of Vancouver, British Columbia in May of 2005 to validate and verify the modeling procedure's ability to simulate and predict blast-induced liquefaction events. Reasonable correlations between predicted and measured data were observed from the study.

This study explores shallow lake numerical hydrodynamic processes that support model development and validation, extreme events and effects of water circulation in Lake Victoria. Lake Victoria is the second largest freshwater lake in the world, and the largest in East Africa. It is the major freshwater reservoir and source for domestic, agriculture, industrial, fishery, and transport. The resources support livelihoods and ecosystem services for over 40 million people. The lake is severely affected by water quality degradation by pollution. This thesis aims at improving the understanding by following recommendation of the Lake Victoria Environment Management Project, Lake Victoria Basin Commission climate change adaptation strategy and action plan 2018-2023, Lake Victoria Basin Commission operational plan 2015-2020, and Lake Victoria Basin Commission report. These reports suggested detailed lake bathymetry survey, modelling of lake flow, study of lake hydrometeorological processes by modelling and simulation, to identify extreme weather events, assess water circulation effect, and study lake pollution near the shore. A numerical hydrodynamic model was built in the COMSOL Multiphysics (CM) software for assessing lake flows and water turn-over from river inflows which carry pollution. The work included the development of systematic methods for lake bathymetry that are relevant for lake numerical and hydrodynamic modelling. The hydrometeorological driven simulation model was employed to assess lake water balance, water circulation and soluble transport. Paper 1 creates a bathymetry from several methods and from several data sources, and a vertically integrated free surface flow model was implemented in CM. The model was used to investigate outflow conditions, mean velocities driven by river inflow, outflow, precipitation and evaporation. It is shown to be exactly conservative and give water level variation in reasonable agreement with measurements. The results indicate that the shallow water model is close to linear. An outflow model, linear in water level, predicts water level reasonable agreement with measurements. The findings suggest that the model should consider wind stress driven flow to provide more accurate lake flow behavior. Paper 2 performed an assessment of the hydro-meteorological processes and extreme weather events that are responsible for changing the characteristics of lake water balance, and changing streamflow variations, and lake transportation. We compare historical data over a long time with data from the model including water balance, sources of data uncertainty, correlations, extreme rain and inflow years, and seasonal variations. Solute loading and transportation was illustrated by tracing the water from the river inflows. The results indicate that the lake rainfall has a strong seasonal variation with strong correlations between tributary inflows and precipitation, and between lake outflow and water level. The tracer transport by mean flow is very slow. Flow increases somewhat in wet periods and is faster in the shallow Kenya lake zone than in the deeper Uganda and Tanzanian lake zones, where the major inflow, from the Kagera River, appears to strongly influence transportation. / Denna studie undersöker med numerisk metodik hydrodynamiska processer i den mycket grundaVictoriasjön och hur de påverkas av extrem väderlek, inflöden, och nederbörd. Victoriasjön är denandra största sötvattensjön i världen, och den största i Afrika. Den är färskvattenförråd och källa förhushåll, jordbruk, industri, fiske och transporter. Resurserna ger livsuppehåll och ekosystemtjänsterför mer än 40 miljoner människor. Sjön är utsatt för allvarliga föroreningar som försämrarvattenkvaliteten. Detta arbete avser att förbättra förståelsen genom att följa rekommendationer somgivits ut av Lake Victoria Environment Management Project (LVEMP), och Lake Victoria BasinCommissions (LVBC) rapporter om strategi för anpassning till klimatförändringar, åtgärdsplan2018-2023 och översiktsplan 2015-2020. Rapporterna föreslår detaljerad genomgång avdjupkartor, modellering av strömning i sjön i syfte att identifiera extrema väderhändelser,undersöka vattencirkulationen, och studera föroreningarna nära stränder. En hydrodynamisknumerisk modell har byggts i simuleringspaketet COMSOL Multiphysics (CM) för uppskattning avströmning och vattenutbyte från förorenade inflöden. Arbetet innefattade utveckling av metoder förvattendjups-modeller för hydrodynamiska studier. Simuleringsmodellen drivs avhydrometeorologiska data och används för vattenmängds-balans, cirkulation ochföroreningstransport.Artikel 1 skapar vattendjupskartan från flera data-mängder med olika metoder. En vertikaltintegrerad modell med fri yta implementerades i CM. Modellen ger vertikalt medelvärdesbildadehastigheter drivna av flodinflöden, utflöde, nederbörd och avdunstning. Modellen representerarvattenbalansen exakt och ger variationer i vattennivå i rimlig överensstämmelse med mätningar.Resultaten antyder att modellen är nära linjär och tids-invariant. En utflödesmodell ansatt somlinjär i vatten-nivån kan anpassas noggrant till historiska data. Bättre realism kan uppnås omvindens pådrivande verkan inkluderas.Artikel 2 går igenom de hydro-meteorologiska processer och extrema väder-händelser som ändrarvattenbalans, strömningsmönster och transport. Vi har jämfört data över femtio år med modellens,inkluderande vattennivå, källor för osäkerhet i data, korrelationer, år med extrema regn ochinflöden, och årstidsvariationer. Resultaten tyder på att nederbörden varierar kraftigt medårstiderna, och signifikanta korrelationer ses mellan nederbörd och inflöden, och mellan utflöde ochvattennivå.Transport av lösliga föroreningar illustrerades genom spårning av vatten från de olika inflödena.Spårämnestransport med vertikalt medelvärdesbildade hastigheter är mycket långsam.Strömningen ökar något i våta årstider och är snabbare i den grunda zonen i Kenya än i de djuparedelarna i Uganda och Tanzania. Det största inflödet som kommer från Kagera tycks ha stor inverkanpå transporten. / <p>QC 20191106</p>