The need to know how river morphology changes due to sedimentation is increasingly important as we attempt to predict future events. Engineers use numeric models to predict effects of changed morphology on river systems. The numerical model Two-dimensional Unsteady Flow (TUFLOW) has recently added, and is continually improving, its capability to model sediment transport in rivers and coastal systems. This paper evaluates the new tools for modeling sediment transport presently contained within TUFLOW and compares these tools with analytical and laboratory case studies. Currently TUFLOW simulates combined bed and suspended load transport of noncohesive sediments under the effect of currents using the Van Rijn method. New TUFLOW capabilities which have not been extensively tested before include recognized sediment transport relationships such as those of Meyer-Peter and Mueller, Bagnold, and Ackers & White. It is important to note that the software evaluated herein is a snapshot of a continuing software development process. The aim of the TUFLOW developers is to address any shortcomings outlined in this paper where feasible. Eleven different test cases are modeled in the Surface-water Modeling System (SMS) software. The test cases are designed to examine how well TUFLOW simulates sediment transport modeling with channels of varying degrees of slope and contractions. Eight of the test cases are taken from Analysis of the Sediment Transport Capabilities of FESWMS. Three cases simulate a simple flume with varying midsection slopes. Four cases use a simple flume with no slope and different contractions: a short abrupt contraction, a long abrupt contraction, a long gradual contraction, and a wide contraction. Two of the test cases are from laboratory flume experiments that were performed at St. Anthony Falls Laboratory. The last test case consists of a river entering a reservoir. The results show that TUFLOW is presently capable of representing sediment transport and morphology reasonably on moderate and shallow slopes and channels with contractions. However, more work is required to improve TUFLOW's morphological capabilities on steep slopes when hydraulic jumps are present. The results show TUFLOW can handle long term simulations. The results show that TUFLOW is not capable at this time of recreating the lab flumes and more features need to be added to accurately portray the flumes. TUFLOW did show perturbations, common for semi-coupled models, in the results for certain test cases. Filtering, a common way of removing perturbations was implemented and gave varying results. The developers are in the process of developing a more advanced scheme for filtering.

Heat transfer brought about by impinging jets is common in several industrialapplications such as the cooling of heated objects. The purpose of this investigationis to create a numerical model of an impacting jet, then to use it in parametricresearch and in the cooling of an electronic device. In this work, COMSOL Multiphysics software has been used to carry out a numericalanalysis of a cooling jet impacting a vertical surface. Water and air are the two fluidscompared to each other, and three different materials were selected for modelling theheated object. The model created can be used in many areas. For example, the caseof the air jet hitting an aluminum object is commonly used in the cooling of electronicdevices while the water jet hitting a brick is used in building and construction. Inother words, the highlight of this project is to create a useful tool that can be easilymodified in order to investigate a specific area. To set an example, the cooling of aninsulated gate bipolar transistor (IGBT) has been investigated in this work. Equations related to the conservation of mass and momentum, coupled to the energyconservation equation, have been solved. Several assumptions were carefully andreasonably considered to simplify the simulation and ensure the accuracy andreliability of the results. The effect of the type of the heated material and the distancebetween the tube nozzle and the heated object have been investigated in the study.The results show that the jet is effective in cooling heated objects and can be used inparametric research. In fact, surface temperature and jet velocity have been displayedand discussed and it has been found that the most optimal combination for efficientheat transfer is a shorter distance between the tube nozzle and the heated object, amaterial with higher thermal conductivity, and water as the jet fluid. The impingingjet device has been tested in the cooling of Insulated Gate Bipolar Transistor (IGBT)and the results showed that the temperature of the IGBT drops by 14.57%. Despite the accuracy of the results, it is important to recognize the limits of thenumerical model such as the discretization of the physical domain, the resolution ofthe mesh, the assumptions, and the simplifications. In addition, this investigation waslimited to three variable factors. Therefore, further studies are recommended tofurther optimize the cooling effect of the jet, such as the study of nozzle shape, jetvelocity, jet mass flow rate and a 3D-simulation. / Värmeöverföring som orsakas av påverkande strålar är vanligt förekommandeinom flera industriella tillämpningar, såsom kylning av uppvärmda objekt. Syftetmed denna undersökning är att skapa en numerisk modell av en påverkande stråleoch sedan använda den i parametrisk forskning och för att kyla en elektroniskenhet. I detta arbete har COMSOL Multiphysics-programvaran använts för att genomföraen numerisk analys av en kylstråle som påverkar en vertikal yta. Vatten och luft ärde två vätskor som jämförs med varandra, och tre olika material valdes för attmodellera det uppvärmda objektet. Den skapade modellen kan användas inommånga områden. Till exempel används fallet med luftstrålen som träffar ettaluminiumobjekt vanligtvis vid kylning av elektroniska enheter, medanvattenstrålen som träffar en tegelsten används inom bygg- ochkonstruktionsbranschen. Med andra ord är höjdpunkten i detta projekt att skapa ettanvändbart verktyg som lätt kan modifieras för att undersöka ett specifikt område.Som ett exempel har kylningen av en isolerad gatebipolär transistor (IGBT) undersökts i detta arbete.  Ekvationer relaterade till mass- och rörelsebevarande, kopplade tillenergibevarelsesekvationen, har lösts. Flera antaganden beaktades noggrant ochrimligtvis för att förenkla simuleringen och säkerställa noggrannheten ochtillförlitligheten hos resultaten. Effekten av uppvärmt materials typ och avståndetmellan tubmunstycket och det uppvärmda objektet har undersökts i studien.Resultaten visar att strålen är effektiv för att kyla uppvärmda objekt och kananvändas inom parametrisk forskning. Faktum är att yttemperaturen och strålenshastighet har visats och diskuterats, och det har konstaterats att den mest optimalakombinationen för effektiv värmeöverföring är ett kortare avstånd mellantubmunstycket och det uppvärmda objektet, ett material med högre termiskledningsförmåga och vatten som strålens fluid. Den påverkande strålenheten hartestats för att kyla en isolerad gatebipolär transistor (IGBT) och resultaten visadeatt temperaturen på IGBT sjunker med 14,57%. Trots resultatens noggrannhet är det viktigt att erkänna begränsningarna hos dennumeriska modellen, såsom diskretiseringen av det fysiska området, upplösningenpå nätet, antaganden och förenklingar. Dessutom var denna undersökningbegränsad till tre variabla faktorer. Därför rekommenderas ytterligare studier för attytterligare optimera strålens kylningseffekt, såsom studiet av munstyckets form,strålens hastighet, strålens massflödesintensitet och en 3D-simulering.

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Traditionally geothermal energy utilizes naturally occurring steam or hot water trapped in permeable rock formations through naturally occurring extraction wells or by implementing the hydraulic fracturing process by fracturing rock formations with water-based fracturing fluids. In contrast, in Enhanced Geothermal System (EGS) hydraulic fracturing process is utilized to create new or reopen existing fractures by injecting high-pressure fluid into deep Hot Dry Rocks (HDR) under carefully controlled conditions. Fracturing fluids are usually water-based that utilize an immense quantity of water. In EGS, they are essential for conducting hydraulic fracturing which bring the concern of technical approach and environmental impact. Thus, an alternative approach is to use waterless fracturing technologies, such as foam-based fracturing fluid. Foams are a complex mixture of the liquid and gaseous phases, where the liquid phase act as an ambient phase and gas is the dispersed phase. Foam fracturing fluids offer potential advantage over conventional water-based fracturing fluids, including reduced water consumption and environmental impact. Although foam-based fracturing has shown promising results in oil and gas industries, its feasibility has not been demonstrated in EGS conditions that usually involve high temperature and high pressures. One potential barrier to utilizing foam as fracturing fluid in EGS applications is that foams are thermodynamically unstable and will become more unstable with increasing temperature due to phenomena such as liquid drainage, bubble coarsening, and coalescence. Therefore, it is essential to stabilize foam fluids at high temperatures for EGS related applications such as fracking of HDRs. This project aims to evaluate the thermodynamic behavior of foams at high temperature and high pressure conditions closely resembling the geothermal environment. In this research, foam behavior was categorized as foam stability based on its half-life, i.e., the time taken by the foam to decrease to 50% of its original height. A laboratory apparatus was constructed to evaluate the foam half-life for a temperature range of room temperature to 200°C and a pressure range of ambient pressure to > 1000 psi. Two types of dispersed/gaseous phases, nitrogen gas (N2) and carbon dioxide gas (CO2), were investigated. Four different types of commercial foaming agents/surfactants with various concentrations were tested, including alfa olefin sulfonate (AOS), sodium dodecyl sulfonate (SDS), TergitolTM (NP – 40), and cetyltrimethylammonium chloride (CTAC). Moreover, five stabilizing agents, guar gum, bentonite clay, crosslinker, silicon dioxide nanoparticles (SiO2), and graphene oxide dispersions (GO), were also added to the surfactants to enhance foam stability. Experimental results showed that N2 foams were more stable than CO2 foams. It was observed that foam half-life decreased with the increase in temperature. Among all the surfactants, AOS foams showed the most promising thermal stability at high temperatures. Moreover, with the addition of stabilizing agents, foam's half-life was enhanced. Stabilizing agents such as crosslinker and GO dispersion showed the most stable foams with half-life recorded at 20 min and 17 min, respectively, at 200°C and 1000 psi. Finally, pressure also showed a positive effect on foam stability; with increased pressure, foam half-life was increased. Based on the experimental data, analytical models for the effect of temperature and pressure were developed, considering foam degradation is a first-order kinetic reaction that linearly depends on the foam drainage mechanism. The effect of temperature on foam half-life was studied as an exponential decay model. In this model, foam half-life is a function of drainage rate constant (DA) and activation energy (Ea) of the foam system. The effect of pressure on foam half-life was found to obey a power-law model where an increase in pressure showed an increase in foam half-life. Furthermore, a linear relation was studied for the effect of pressure on foam activation energy and drainage rate. Then the, combined effects of temperature and pressure were studied, which yielded an analytical model to predict the foam stabilities in terms of half-life for different foam compositions. This research indicates that with an appropriate selection of surfactants and stabilizing agents, it is possible to obtain stable foams, which could replace conventional water fracturing fluid under EGS conditions. / Mechanical Engineering

Wind-tunnel measurements are an important step during the windturbinedesign process. The goal of wind-tunnel tests is to estimate theoperational performance of the wind turbine, for example by measuringthe power and thrust coecients. Depending on the sizes of both thewind turbine and the test section, the eect of blockage can be substantial.Correction schemes for the power and thrust coecients havebeen proposed in the literature, but for high blockage and highly loadedrotors these correction schemes become less accurate.A new method is proposed here to calculate the eect a cylindricalwind-tunnel test section has on the performance of the wind turbine.The wind turbine is modeled with a simplied vortex model. Usingvortices of constant circulation to model the wake vortices, the performancecharacteristics are estimated. The test section is modeled witha panel method, adapted for this specic situation. It uses irrotationalaxisymmetric source panels to enforce the solid-wall boundary condition.Combining both models in an iterative scheme allows for thesimulation of the eect of the presence of the test-section walls on windturbines performace.Based on the proposed wind-tunnel model, a more general empirical correlationscheme is proposed to estimate the performance characteristicsof a wind turbine operating under unconned conditions by correctingthe performance measured in the conned wind-tunnel conguration.The proposed correction scheme performs better than the existing correctionschemes, including cases with high blockage and highly loadedrotors.

The waste management and recycling company, Söderhalls Renhållningsverk (SÖRAB) have constructed a surface flow wetland in order to treat surface runoff from the waste management site, Löt. The contaminated water passes several treatment steps until it reaches the wetland and a subsequent soil infiltration step. It is suspected that the flow path of the water through the wetland is short-circuited which may result in a reduced treatment efficiency. The current discharge concentrations of the chemical compounds tested for do not exceed the allowed discharge limits. However, it is of interest to keep the discharge concentrations as low as possible to protect sensitive areas and water bodies downstream. The aim of the thesis was therefore to investigate the flow pattern of the wetland and suggest measures which potentially could improve the treatment efficiency. The flow pattern was modelled numerically in a Physio-Mathematical model developed by Wörman and Kjellin (2020). The current flow pattern was modelled, followed by several simulation runs where the controlling factors of the flow were changed one by one. The validity of the modelling result is uncertain and should therefore be confirmed or rejected by conducting a tracer test prior to implementing any changes in the wetland design. The modelling results indicate the presence of a main flow path passing through the narrower section of the permeable embankment (intersecting the northern and southern part of the wetland, see Fig. 3). The results further indicate that the permeable embankment, the bottom topography and the vegetation distribution were the three major factors controlling the flow pattern within the wetland. Recommended improvements would therefore be to first conduct a tracer test to make sure that any changes implemented are based on the true current flow pattern. The embankment and the vegetation distribution seem to be the main causes of non-idealities in the flow but at the same time probably also have positive effects on the treatment efficiency (since they provide filtration and surface areas where microorganisms can attach to perform their treatment). One solution to reduce the non- idealities in the flow could therefore be to adjust the embankment to be equally wide and deep across the wetland. Furthermore, the bottom topography around the embankment could be adjusted so that the shift in bottom elevation is equal around it. This would probably aid in hindering the development of preferential flow paths through the embankment. Finally, the vegetation distribution could be made uniform. (It should also be noted that a uniform vegetation distribution would require adjustment of the water depth to be below 1,5 m to allow an equal establishment of vegetation). / Avfallshanterings- och återvinningsföretaget Söderhalls Renhållningsverk AB (SÖRAB) har anlagt en våtmark vid Löts avfallsanläggning, ca 35 km norr om Stockholm. Våtmarken utgör det näst sista reningssteget i reningsprocessen av lak- och processvatten från avfallsanläggningen. Riktvärdena för utsläppshalterna överskrids inte men det är önskvärt för SÖRAB att åstadkomma så låga utsläppsvärden som möjligt för att minimera påverkan på känsliga områden och vattendrag nedströms. SÖRAB misstänker dock att preferentiella flödesvägar kan förekomma där vattnet passerar alltför fort genom våtmarken. Detta resulterar ofta i en lägre reningseffektivitet då föroreningarna som är lösta i vattnet får en kortare kontakttid med de naturliga reningsmekanismerna som förekommer i våtmarken. Syftet med det här arbetet var därför att undersöka strömningen i våtmarken och identifiera vattnets flödesvägar med hjälp av en numerisk modell utvecklad av Wörman och Kjellin (2020). Strömningen i våtmarker styrs av en energigradient där flödet går från en punkt i ett vattendrag med högt energiinnehåll till en punkt med lågt energiinnehåll. Enligt principen om energins bevarande omvandlas energin mellan kinetisk, potentiell, tryckenergi och värmeenergi. Ändringen i energiinnehåll beror i sin tur på verkan av externa krafter (gravitationskraften, hydrostatiska tryckkrafter, friktionskrafter, kontraktions- och expansionskrafter och skjuvkrafter från vind. Dessa krafter verkar vid förändringar i bottentopografin, vattendjupet, ytmotståndet (vid våtmarkens botten och väggar), våtmarkens geometri samt där vattenytan är exponerad för vind. Dessa faktorer orsakar utvecklandet av skjuvkrafter i flödet som i sin tur orsakar utvecklandet av hastighetsprofiler och omblandning. Bildandet av hastighetsprofiler och omblandning av vattnet gör att olika vätskeelement eller föroreningar stannar i våtmarken olika lång tid då de rör sig olika fort. För att åstadkomma en så hög reningsgrad som möjligt är det därför önskvärt att hela våtmarkens volym nyttjas till samma grad och att samtliga vätskeelement rör sig med samma hastighet genom våtmarken vilket även kallas för en ideal flödesregim (där ingen omblandning i flödesriktningen förekommer). Då utvecklandet av skjuvkrafter i flödet utgör den grundläggande orsaken till avvikelser från en ideal flödesregim är det önskvärt att minimera dessa. De styrande faktorerna som orsakade utvecklandet av skjuvkrafter i flödet var som nämndes ovan: variationer i våtmarkens bottentopografi och vattendjup, våtmarkens geometri (som kan orsaka isolerade vattenvolymer), ytmotståndet (som bl.a. beror på distributionen av vegetation), vind, samt in- och utflödeshastigeter. Våtmarken undersöktes genom inmätning och lodning som sedan låg till grund för en konceptuell modell av systemet. Den konceptuella modellen utgjorde sedan en grund för att modellera våtmarken numeriskt. I den konceptuella modellen ingick identifiering och definition av systemgränser samt randvillkor, att definiera bottentopografin samt att dela in våtmarken i delområden med homogent flödesmotstånd. Systemgränser och randvillkor identifierades baserat på en vattenbalans. Med hjälp av vattenbalansen kunde relevanta komponenter att inkludera som randvillkor identifieras. Randvillkorens värden bestämdes genom mätningar av den hydrauliska potentialen med hjälp av en GNSS-mottagare (där GNSS står för Global Navigation Satellite System och mottagaren nyttjar satelliter för att bestämma höjd och position i en geografisk punkt) samt från erhållna mätvärden från SÖRAB av in- och utflöden som pumpas in och ut ur våtmarken. Då bottentopografin var okänd bestämdes den genom att vattendjupet mättes, interpolerades och subtraherades från en referensnivå. Vattendjupet mättes genom lodning och mätpunkterna interpolerades sedan i det geografiska informationsverktyget ArcMap för att erhålla ett heltäckande lager av mätvärden över vattendjupet. Därefter kunde vattendjupet subtraheras från vattenytans medelhöjd över havet vilket var 38,1 m och ett heltäckande lager över bottentopografin kunde erhållas. Flödesmotståndet beräknades enligt ekvation 16 (se avsnitt 2.1.) och våtmarken delades in i homogena delområden baserat på förekomsten av vegetation och om strömningen skedde genom ett poröst medium eller öppet vatten. Den numeriska modelleringen genomfördes genom att först modellera den nuvarande strömningen med och utan ett rör som går genom den genomsläppliga vallen. Därefter ändrades de styrande faktorerna för flödet en i taget för att kunna utvärdera vilken effekt varje faktor hade på strömningen i våtmarken för att åstadkomma en ideal flödesregim. Följande simuleringar genomfördes: (1) Bottentopografin gjordes jämn med ett vattendjup på 0,5 respektive 1,0 m, (2) inloppszonen gjordes längre för att undvika skapandet av isolerade vattenvolymer längs ytterkanterna, (3) vegetationens distribution gjordes homogen, (4) den genomsläppliga vallen justerades. Pålitligheten i resultatet från den numeriska modelleringen är osäker. Därför skulle ett spårämnesförsök behöva genomföras för att undersöka huruvida resultatet från modelleringen är tillförlitligt eller inte. Enligt modelleringsresultatet förekom en tydlig flödesväg som passerade genom den smalare delen av vallen. Modelleringen indikerade vidare att de kontrollerande faktorerna som styrde flödet i våtmarken framförallt utgjordes av distributionen av vegetation samt den genomsläppliga vallen tillsammans med omgivande bottentopografi. Det rekommenderas därför att modelleringsresultatets validitet först undersöks med ett spårämnesförsök innan några åtgärder vidtas. Möjliga förbättringsåtgärder som skulle kunna införas därefter för att sträva mot ett idealt flöde skulle kunna vara att justera den genomsläppliga vallen till att ha en lika stor tjocklek och ett lika stort djup överallt samt att justera bottentopografin runt vallen så att den förändras lika mycket runt vallen. Detta för att skapa förutsättningar för att undvika preferentiella flödesvägar genom den. En jämn fördelning av vegetation (och justering av vattendjupet till att understiga 1,5 m som tillåter kolonisering av växter) att störningar i flödet minimeras.

Subduction is a dynamic and time-dependent process which requires time-dependent models for its study. In addition, due to the very high pressures within the Earth's interior, an evaluation of the role of compressibility in subduction studies should be undertaken. However, most subduction studies have been conducted by using kinematic, steady-state, and/or incompressible mantle convection models; these simplifications may miss important elements of the subduction process. In this dissertation, I evaluate the effects of time-dependence and compressibility on the evolution of subduction by using 2-D Cartesian numerical models. The effect of compressibility on the thermal and flow structures of subduction zones is evaluated by using kinematically prescribed slab and steady-state models. The effect of compressibility is primarily expressed as an additional heat source created by viscous dissipation. The heat results in thinner thermal boundary layer on the subducting slab and increases slab temperatures. With that exception, the effect of compressibility is relatively small compared with, for example, the effect of the mantle rheology on the thermal and flow structures of the mantle wedge. Plate reconstruction models show that the convergence rate and age of the incoming plate to trench vary with time, which poses a problem for steady-state subduction models. Thus, I consider the time-dependent convergence rate and age of the incoming plate in the kinematic-dynamic subduction models in order to understand the localization of high-Mg# andesites in the western Aleutians. The results show that the localization of high-Mg# andesites is a consequence of the time-dependent convergence rate and slab age along the Aleutian arc. The influence of mantle and slab parameters as well as compressibility on the slab dynamics is evaluated by using 2-D dynamic subduction models. The results demonstrate that periodic slab buckling in the mantle results in periodic convergence rate and dip of the subducting slab; time-dependence is a natural expression of subduction. The effect of compressibility on the slab dynamics is not significant. The periodic convergence rate and dip of the subducting slab explain time-dependent seafloor spreading at the mid-ocean ridge, convergence rate of the oceanic plate at trench and arc-normal migration of arc volcanoes. / Ph. D.

Prestressed Concrete Cylinder Pipe (PCCP) is a large-diameter and high-pressure conduit for drinking water and wastewater transmission. Due to its large diameter, high pressure, and mode of breakdown, PCCP failures usually have catastrophic consequences. To mitigate failures, it is very important to assess the condition of the pipe and take proactive measures, such as repair, rehabilitation, or replacement. There are many challenges in assessing the condition of PCCP. PCCP has a complex structure with several layers of materials (e.g. mortar coating, prestressing wire, steel cylinder, and concrete core) working together under loading. This means that there are many factors that can cause pipe failure, and that failure mechanisms are complicated. Data collection could be difficult, and existing data are often unavailable or unreliable. Considerable research has been conducted by scholars and engineers in developing models to evaluate the condition of PCCP. There are mainly two types of models: statistical models, and numerical models using finite element method. Statistical models consider only a few factors, such as pipe age and failure rate, to predict the failure of PCCP. However, the failure of PCCP can be caused by many other factors including pipe material, and loading conditions. Models only considering a few factors are not robust enough for reliable results. The current numerical models assume that all broken wires are centrally distributed in the same location and broken wires have no prestress, thus all broken wires are completely removed from the model. These assumptions could be overly conservative when actual broken wires are distributed in different locations along the pipeline and broken wires have remaining prestress due to the bond between the wire and mortar coating. Therefore, a more comprehensive numerical model is needed to have a better understanding of the condition of PCCP. In this research, an extensive literature and practice review was conducted on PCCP failures to understand the critical factors that affect pipe condition. The available technologies commonly used to detect pipe defects were reviewed in order to better understand the accuracy and uncertainties of the collected data. Existing models were reviewed to better understand their limitations and to advance the research on condition analysis of PCCP using numerical models. Based on these comprehensive reviews, this dissertation proposed a numerical model to analyze the condition of PCCP for its long-term performance management. Detailed structural components such as concrete cores, prestressing wires, steel cylinder, and mortar coating were modelled. The interactions between different layers of pipe components were considered. An algorithm was proposed to account for the bond between the prestressing wire and mortar coating, which is a critical factor for the condition of PCCP with broken wires. A FORTRAN program was developed to assign linear stress distribution between the broken point and the full-prestress resuming point. The proposed numerical model was verified utilizing data from lab tests and forensic study. Lab test data helped to understand the functionality of the model and to verify the model parameters used in analyzing pipe components and the simulation of interactions between different layers. The forensic data helped to verify the model under actual field working conditions of the pipe. Validation of the proposed numerical model was conducted using a 66-inch Embedded Cylinder Pipe and two Lined Cylinder Pipes (42-inch and 48-inch, respectively) from a water utility. In the validation, field data were collected for model development. The simulation results were consistent with the field observation, which proved the validity and applicability of the proposed numerical model in practice. A series of sensitivity studies were conducted to investigate the impact of longitudinal and circumferential location on the structural integrity of the pipe. These investigations showed that considering the actual longitudinal and circumferential location of broken wires is very important to get accurate analysis of pipe condition, while assuming that all broken wires fail in one longitudinal location (assumptions by current numerical models for PCCP) will overestimate the actual damage to the pipe caused by broken wires. To consider the bedding condition, a critical factor for PCCP, the four most common bedding types found in practice were analyzed. Results show that poor bedding could lead to cracks in PCCP, which could cause corrosion in prestressing wires. Therefore, it is very important to account for bedding conditions in the PCCP analysis. The model presented in this dissertation is more comprehensive and robust compared with existing numerical models, and could provide a better understanding of the condition of PCCP. This is because the proposed model considers the contribution of remaining prestress in broken wires due to the bond between the wire and mortar coating. This model can consider the actual longitudinal and circumferential location of broken wires rather than centrally distribute them, and it can consider the actual bedding locations, and the interaction between different layers of materials. This model was calibrated using lab test data and forensic data, and was further validated using field data which showed consistence between simulation results and field observations. The proposed model does have limitations due to limited availability of data and assumptions. Material tests were not conducted to verify the material properties used in the model, which could cause accuracy issues in the results. A full-scale simulation of the interaction between prestressing wire and mortar coating was not considered because it could significantly increase the computation time. Lab tests were not conducted to verify the parameters used for the simulation of interaction between concrete core and steel cylinder which could lead to accuracy problems. Finally, it is acknowledged that the model was only validated in one water utility and validations in more geographically distributed utilities might further test the model's validity and robustness. Nonetheless, the comprehensiveness and robustness of this proposed model improved the analysis of the condition of PCCP. The findings and results of this research will provide guidance for better management of PCCP pipelines for water utilities, and provide reference for future research on numerical modeling of PCCP as well. / Ph. D.