Next generation nuclear power plants (GEN-IV) will be capable of not only producing energy in a reliable, safe and sustainable way, but they will also be capable of reducing the amount of nuclear waste, which has been accumulated over the lifetime of current-generation nuclear power plants, through transmutation. Due to the use of new and different coolants, existing computational tools need to be tested, further developed and improved in order to thermal-hydraulically design these power plants.This work covers two different non-unity Prandtl number fluids which are considered as coolants in GEN-IV reactors, liquid lead/lead-bismuth-eutectic and supercritical water. The study investigates different turbulence modeling strategies, such as Large Eddy Simulation (LES) and Reynolds-Averaged Navier-Stokes (RANS) modeling, and their applicability to these proposed coolants. It is shown that RANS turbulence models are partly capable of predicting wall heat transfer in annular flow configurations. However, improvements in these prediction should be possible through the use of advanced turbulence modeling strategies, such as the use of separate thermal turbulence models. A large blind benchmark study of heat transfer in supercritical water showed that the available turbulence modeling strategies are not capable of predicting deteriorated heat transfer in a 7-rod bundle at supercritical pressures. New models which take into account the strong buoyancy forces and the rapid change of the molecular Prandtl number near the wall occurring during the transition of the fluid through the pseudocritical point need to be developed. One of these strategies to take into account near-wall buoyancy forces is the use of advanced wall functions, which cannot only help in modeling these kind of flows, but also decrease computational time by 1 to 2 orders of magnitude. Different advanced wall function models were implemented in the open-source CFD toolbox OpenFOAM and their performance for different flows in sub- and supercritical conditions were evaluated. Based on those results, the wall function model UMIST-A by Gerasimov is recommended for further investigation and specific modeling tactics are proposed.Near-wall temperature and velocity behavior is important to and influenced by the wall itself. The thermal inertia of the wall influences the temperature in the fluid. However, a more important issue is how temperature fluctuations at the wall can induce thermal fatigue. With the help of LES thermal mixing in a simplified model of a control rod guide tube was investigated, including the temperature field inside the control rod and guide tube walls. The WALE sub-grid turbulence model made it possible to perform LES computations in this complex geometry, because it automatically adapts to near-wall behavior close to the wall, without the use of ad-hoc functions. The results for critical values, such as the amplitude and frequency of the temperature fluctuations at the wall, obtained from the LES computations are in good agreement with experimental results.The knowledge gained from the aforementioned investigations is used to optimize the flow path in a small, passively liquid-metal-cooled pool-type GEN IV reactor, which was designed for training and education purposes, with the help of 3D CFD. The computations were carried out on 1/4 of the full geometry, where the small-detail regions of the heat exchangers and the core were modeled using a porous media approach. It was shown that in order to achieve optimal cooling of the core without changing the global geometry a ratio of close to unity of the pressure drop over the core and the heat exchanger needs to be achieved. This is done by designing a bottom plate which channels enough flow through the core without choking the flow in the core. Improved cooling is also achieved by reducing heat losses from the hot leg through the flow shroud to the cold leg by applying thermal barrier coating similar to methods used in gas turbine design. / Nästa generations kärnkraftverk (GEN-IV) kan inte bara producera el på ett pålitligt, säkert och hållbart sätt, utan det kan också reducera mängden kärnavfall, som har producerats under tiden som man använt nuvarande generationen kärnkraftverk, genom att transmutera avfallen. Framtidens kärnkraftverk använder andra kylmedel än nuvarande kraftverk som t.ex. flytande bly, gas eller superkritiskt vatten. Det betyder att många beräkningsverktyg måste testas, utvecklas och förbättras så att man kan genomföra termohydrauliska designberäkningar. Den här avhandlingen omfattar två olika kylmedel, flytande bly och superkritiskt vatten, som har ett Prandtl-tal som skiljer sig från 1 och kommer att användas i GEN-IV reaktorer. Studien undersöker olika strategier för att modellera turbulens som Large Eddy Simulation (LES) och Reynolds-Averaged Navier-Stokes (RANS) och hur man kan använda dessa strategierna i beräkningar av strömning och värmetransfer i den nya kylvätskan. Undersökningen visar att RANS turbulensmodeller delvis kan förutsäga värmeöverföringen vid en vägg i en ringformad strömningsgeometri. Förbättringar av förutsägelsen ska vara möjlig genom användning av avancerade strategier för turbulensmodellering, t.ex. termiska turbulensmodeller. En stor prestandajämförelse för värmeöverföring i superkritiskt vatten visade att ingen av nuvarande strategier för turbulensmodellering kan förutsäga försämrad värmeöverföring i en 7-stavknippet under superkritiskt tryck. Nya modeller, som omfattar de starka flytkrafterna och den snabba förändringen av den molekulära Prandtl-tal vid väggen som uppstår när vätskan går genom pseudokritiska punkten, måste utvecklas. Avancerade väggfunktioner är en av strategierna som kan ta hänsyn till dessa fenomen. Väggfunktioner kan inte bara hjälpa till att modellera de typer av flöden som behövs utan kan också hjälpa till att sänka beräkningstiden med en eller två tiopotenser. Olika avancerade väggfunktioner i open-source beräkningsverktyget OpenFOAM implementerades och deras prestation i sub- och superkritiska vattenflödar värderades. Baserat på detta rekommenderas Gerasimovs modell för ytterligare utredning. Dessutom läggs olika strategier fram för att utöka modellens validitet till flöde med superkritiskt vatten i sammanband med försämrad och förbättrad värmeöverföring. Kunskap om beteendet av temperatur och hastighet i väggens närhet är viktigt för väggens integritet, detta då väggen även påverkar beteendet. Väggens termiska tröghet påverkar flödets temperatur och hastighet. Dock är ett ännu viktigare problem, som kan uppträda, är att temperaturfluktuationer kan framkalla termisk utmattning i en vägg. Med användning av LES utreds termisk blandning av varmt och kallt vatten i en simplifierad modell av ett styrstavsledrör, inklusive temperaturfältet i styrstaven och ledrörsväggen. Användningen av WALE LES-turbulensmodellen gör det möjligt att utföra beräkningar i den komplexa geometrin, detta eftersom modellen anpassar sig automatiskt till fenomenen nära väggen utan användning av ad-hoc funktioner. LES resultaten för alla värden som är viktiga för att bestämma utmattningsbeteende, som amplitud och frekvens av temperaturfluktuationer i väggens närhet och i väggen själv, är i god överensstämmelse med resultaten från experiment från KTH i samma geometri.Kunskapen som vunnits genom ovannämnda utredningar användes för att optimera den termohydrauliska designen av en liten, pool-typ GEN-IV reaktor som är passivt kyld med flytande bly. Reaktorn är designad som en utbildnings- och träningsreaktor och optimeringen genomfördes med hjälp av 3D CFD. Beräkningarna genomfördes på en fjärdedel av reaktorns hela geometrin. Regioner med små detaljer, som de åtta värmeväxlarna och reaktorns kärna, modellerades genom porösa material. Det visar sig att för att ha en optimal kylning av kärnan, utan att förändra reaktorns globala geometri, måste förhållandet mellan tryckförlust i reaktorkärnan och värmeväxlarna vara nära 1. Detta uppnås genom att designa plattan vid ingången till kärnan så att tillräckligt med bly flödar genom kärnan utan att kväva flödet i denna. Ytterligare en förbättring i reaktorkylningen uppnås genom att reducera värmeförlusten genom väggen som skiljer varm och kall vätska. Detta görs med en strategi som förekommer i gasturbinteknologin, genom att man lägger till ett tunt skikt av termiskt isolerande material på väggen, som reducerar värmeöverföring med ungefär 50%. / <p>QC 20151123</p> / THEMFA / GENIUS / THINS

Στην παρούσα μελέτη καταγράφεται η αγγειώδης χλωρίδα των τοίχων της πόλης της Πάτρας, καθώς και οι θέσεις των taxa πάνω στους τοίχους. Εντοπιστήκαν 167 taxa. Η χλωρίδα αναλύεται περαιτέρω σε σχέση με την τοπική εξάπλωση των taxa, καθώς και από βιολογική και χωρολογική άποψη και συγκρίνεται η ποικιλότητα και η ποιοτική ομοιότητα της χλωρίδας που εμφανίζεται στους τοίχους του κέντρου, της παραθαλάσσιας και της προαστιακής περιοχής της πόλης. Η ποικιλότητα στο σύνολο της χλωρίδας των τοίχων στην Πάτρα βρέθηκε Η΄= 1,97 και η συνολική τιμή του δείκτη κυριαρχίας Simpson είναι D = 0,23. Tα αποτελέσματα συγκρίνονται με τις χλωρίδες τοίχων άλλων ελληνικών και ξένων πόλεων. Eπίσης, τονίζεται η σπουδαιότητα των τοίχων ως αστικοί βιότοποι και διατυπώνονται προτάσεις για τη σωστή διαχείρισή τους. / The aim of the present study was to survey the wall vascular flora of the Greek city of Patras in SW Peloponnese. 167 taxa were identified. The flora is analysed in relation to the local distribution of the taxa as well as by biological and chorological aspect. There has been comparison between the diversity and the quality similarities among the walls of centre, maritime and suburban transect of the city. The overall diversity found is H = 1,97 and D = 0,23. The results are compared with wall floras of other cities.

No description available.

The present thesis deals with the fundamental aspects of turbulent mixing and non-premixed combustion in the wall-jet flow, which has a close resemblance to many industrial applications. Direct numerical simulations (DNS) of turbulent wall-jets with isothermal and exothermic reactions are performed. In the computational domain, fuel and oxidizer enter separately in a nonpremixed manner and the flow is compressible, fully turbulent and subsonic. The triple “turbulence-chemistry-wall” interactions in the wall-jet flow have been addressed first by focusing on turbulent flow effects on the isothermal reaction, and then, by concentrating on heat-release effects on both turbulence and flame characteristics in the exothermic reaction. In the former, the mixing characteristics of the flow, the key statistics for combustion and the near-wall effects in the absence of thermal effects are isolated and studied. In the latter, the main target was to identify the heat-release effects on the different mixing scales of turbulence. Key statistics such as the scalar dissipation rates, time scale ratios, two-point correlations, one and two-dimensional premultiplied spectra are used to illustrate the heat release induced modifications. Finer small mixing scales were observed in the isothermal simulations and larger vortical structures formed after adding significant amounts of heat-release. A deeper insight into the heat release effects on three-dimensional mixing and reaction characteristics of the turbulent wall-jet flow has been gained by digging in different scales of DNS datasets. In particular, attention has been paid to the anisotropy levels and intermittency of the flow by investigating the probability density functions, higher order moments of velocities and reacting scalars and anisotropy invariant maps for different reacting cases. To evaluate and isolate the Damkohler number effects on the reaction zone structure from those of the heat release a comparison between two DNS cases with different Damkohler numbers but a comparable temperature rise is performed. Furthermore, the wall effects on the flame and flow characteristics, for instance, the wall heat transfer; the near-wall combustion effects on the skin-friction, the isothermal wall cooling effects on the average burning rates and the possibility of formation of the premixed mode within the non-premixed flame are addressed. The DNS datasets are also used for a priori  analysis, focused on the heat release effects on the subgrid-scale (SGS) statistics. The findings regarding the turbulence small-scale characteristics, gained through the statistical analysis of the flow have many phenomenological parallels with those concerning the SGS statistics. Finally, a DNS of turbulent reacting wall-jet at a substantially higher Reynolds number is performed in order to extend the applicability range for the conclusions of the present study and figuring out the possible differences. / <p>QC 20150225</p>

Measurement of all the mechanical properties of carbon nanotubes is extremely difficult because of its small size. In the present work, all the five transverse isotropic properties of single wall carbon nanotubes (SWCNTs) and double wall carbon nanotubes are estimated through molecular structural mechanics for different chirality, length and assumed thickness. Armchair, zigzag & chiral SWCNTs and polychiral DWCNTs are considered for the analysis. Longitudinal and lateral Young’s modulus; longitudinal and lateral Poisson’s ratio and shear modulus are estimated for 1080 SWCNTs and 1170 polychiral DWCNTs. Effect of temperature on all the properties of SWCNT are investigated. Modal characterization of SWCNT is carried out in base fixed condition and different mode shapes viz. axial, torsion and bending mode shapes are identified based on the effective mass. Once the transverse isotropic properties of SWCNTs are estimated, these are used to estimate the transverse isotropic properties of nanocomposites embedded with SWCNT agglomerates. During the manufacturing of nanocomposite, SWCNT agglomerates are formed due to sticking of number of SWCNTs. Parametric studies are carried out to see the effect of SWCNT length on the properties of nanocomposite. Empirical formulae for all the transverse isotropic properties of SWCNT at room temperature and elevated temperature; frequency of SWCNT are derived. Empirical formulae for polychiral DWCNT transverse isotropic properties are estimated. Input for these empirical formulae are the length, chirality and assumed thickness. Empirical formulae were also derived for nanocomposite embedded with different number of SWCNTs having different chirality. The derived empirical formulae were validated with available analytical and experimental results for some sample cases.

É apresentado um estudo sobre a análise de edifícios altos enrijecidos com núcleos estruturais utilizando-se processos discretos. A ligação do núcleo estrutural com as lajes do pavimento do edifício é o ponto principal deste estudo. As vigas, pilares e lajes são analisados utilizando-se o Método dos Elementos Finitos. Os núcleos estruturais, que no presente estudo podem ser de seção aberta ou semifechada, são analisados pela teoria de flexo-torção é levado em consideração o empanamento do elemento do núcleo, dessa forma aparece o esforço denominado bimomento. O empenamento do núcleo estrutural é transferido para as lajes, ocorrendo alteração em sua distribuição de esforços. Para o cálculo da estrutura do edifício como um todo é utilizada a técnica de subestruturação em que o edifício é dividido em subestruturas formadas por um determinado número de andares. Os resultados da forma de cálculo pesquisada são comparados com modelos já desenvolvidos por outros autores. / This is a study about the analysis of tall buildings with shear/core walls using discrete processes. The joining of shear/core with slabs in tall buildings is the main subject of this work. The beams, columns and slabs are analyzed using the Finite Element Method. The building analysis is in 1st order. The shear/core walls, in this study, can present open or semi-closed cross section; they are analyzed by the theory of warping of beams of solid sections. In this theory we consider the warping of the core element, accounting for the bimoment. The warping of the core is transferred to the slabs, and the efforts in the slabs are altered. In order to calculate the building structure we are using the sub-structure technique, the building is divided in substructures created by a certain number of floors. The results of this research are compared with models developed by other authors.

Introdução: O ato da micção é processo complexo que envolve o encéfalo, a medula espinhal, o sistema nervoso periférico e a integridade neuromuscular do trato urinário baixo. Essa integridade permite a ocorrência da fase de armazenamento de urina na bexiga e, a seguir, da fase de esvaziamento vesical. Havendo comprometimento das conexões entre esses componentes, tanto o enchimento quanto o esvaziamento vesical podem estar comprometidos. Conhecendo as propriedades do extensômetro elétrico de resistência, foi proposta a construção de um aparato com capacidade de avaliar a condição de enchimento vesical e que permita a correlação direta com a pressão intravesical. Objetivo: Desenvolver e demonstrar o funcionamento de um equipamento para monitoramento contínuo da tensão do detrusor, em coelhos, durante a fase de enchimento vesical. Material e Métodos: Foram utilizadas 12 coelhas da raça Nova Zelândia. Após anestesia, a bexiga foi exposta por incisão mediana e a uretra foi obstruída com ligadura por fio de algodão. O sensor de tensão foi suturado ao detrusor e confeccionada cistostomia por punção com Abocath 16, utilizada para enchimento e esvaziamento vesical e cistometria, avaliada pelo equipamento Dynamed® - modelo Dynapack MPX-B16. Os coelhos foram submetidos ao procedimento de monitorização inicial (enchimento vesical monitorado pela cistometria) e a medida da tensão da parede vesical - com a bexiga totalmente preservada. Resultados: No decorrer dos experimentos e com a conclusão das análises estatísticas, encontramos uma correlação muito importante entre os dados. Quando se coloca em foco apenas um animal, verifica-se uma grande correlação entre os dados provenientes do volume infundido na bexiga em função da curva gerada para a pressão intravesical que, por sua vez, acompanha fidedignamente a curva da tensão lida na parede vesical do mesmo animal. Quando avaliados conjuntamente, verificasse que os dados são muito próximos uns dos outros, tais como o volume infundido e a tensão final em mV, lida pelo equipamento desenvolvido. Conclusão: O equipamento foi desenvolvido e, com base nos resultados obtidos, mostrou-se adequado para o monitoramento contínuo da tensão vesical do detrusor e sua correlação com o volume vesical, em coelhos, durante a fase de enchimento vesical. / Introduction: Urination is a complex process which involves the brain, the spinal cord, the peripheral nervous system and the neuromuscular integrity of the lower urinary tract. It is the unimpaired condition of all those parts that allows the bladder to go through its functional states - storage phase (filling) and voiding phase (emptying). Problems within these anatomical structures connections can also compromise both phases. This thesis presents the design of a new device which uses an electrical resistance strain gauge to evaluate the bladder\'s filling and its direct correlation with the intravesical pressure. Objective: To develop and demonstrate the operation of a new device that checks continuously rabbit\'s detrusor pressure during bladder filling. Material and Methods: 12 rabbits of New Zealand race were used. After anesthesia, their bladders and urethras were exposed via an abdominal incision made at the midline. Then, the urethra obstruction was performed by ligation using cotton thread. The tension sensor was sutured to the detrusor and a cystostomy puncture was made with an Abocath 16. The puncture was used for filling and voiding cystometry using the urodynamic equipment, Dynamed - Dynapack model MPX-B16. Data collected by this equipment was used as the baseline. Rabbits underwent an initial monitoring procedure, bladder\'s filling cystometry using the Dynamed equipment, and voltage measurement of the bladder wall using the new device - bladder integrity was preserved. Results: During the experimental phase, completion of the statistical analyzes showed us a very significant data correlation. Correlation was stronger when evaluating each animal data individually. The infused volume in the bladder, which was verified by the intravesical pressure curve, and the voltage measured on the bladder wall faithfully followed each other. When evaluating the combined data of all rabbits, correlation was less but still significant. Volume and voltage curves still resembled one another, especially the infused volume with the final voltage reading, in mV. Conclusion - Based on the results of the experimental phase in animals, the developed device is adequate for continuous detrusor pressure monitoring and its correlation with the bladder volume in the storage phase.

Le potentiel de valorisation, aussi bien pour l'alimentation animale que pour la production bioénergétique, du maïs est limité par la lignification et la réticulation des parois. L'amélioration de la dégradabilité enzymatique des lignocelluloses est un objectif important. Nous nous sommes attachés dans ce travail à l'étude approfondie de la mise en place de la lignification dans la paroi chez le maïs ainsi qu'aux facteurs biochimiques et anatomiques pariétaux qui peuvent avoir un impact sur la dégradabilité des parois. Dans la première partie de ma thèse, 8 lignées recombinantes de maïs ont été sélectionnées sur la base d'une teneur en lignine comparable pour évaluer l'impact des facteurs biochimiques sur la dégradabilité des parois et sur les performances agronomiques des maïs. Ces lignées recombinantes et leurs parents ont été analysés biochimiquement de façon approfondie. Le rendement β-O-4 au sein des lignines et la teneur en acide p-coumarique estérifié sont les deux facteurs les plus corrélés négativement et significativement à la dégradabilité des parois. Une analyse par régression multiple a montré que plus de 80% des variations de la dégradabilité de paroi, dans ces dix lignées, sont expliqués par un modèle retenant comme meilleurs régresseurs la teneur en lignines combinée au pourcentage d'unité S acylées par l'acide p-coumarique. L'étude morphologique que nous avons réalisée nous a montré que les facteurs biochimiques limitant la dégradabilité de paroi peuvent par contre s'avérer favorables pour assurer la performance agronomique de la plante via des mécanismes de plasticité pariétale. Cependant et de façon très encourageante, nous avons aussi montré qu'il était tout à fait possible de retenir du matériel amélioré en termes de qualité de paroi et qui conservait de bonnes performances agronomiques. Dans la deuxième partie de ma thèse, nous avons étudié le schéma de mise en place des parois au cours du développement des plantes pour des lignées présentant des teneurs en lignine comparables au stade ensilage mais des dégradabilités de parois contrastées. Nous avons caractérisé biochimiquement les entrenoeuds au cours du développement. En parallèle, nous avons développé une méthode de quantification de la variation de distribution spatiale des lignines au long de la coupe afin de compléter notre étude au cours du développement par une caractérisation histologique détaillée. D'un point de vue temporel, les différentes composantes pariétales sont incorporées graduellement, en fonction du stade de développement. Trois étapes majeures de développement ont été identifiées. D'un point de vue spatial, au sein de l'entrenoeud, le développement des parois est différent selon les régions. Une importante variabilité génétique a été observée pour le développement sur ces deux axes et ces variations sont associées à la variation de la dégradabilité de paroi. L'ensemble des résultats de ce travail est discuté d'une part en termes de contribution à la compréhension de la lignification des parois ainsi qu'à l'impact des différents facteurs biochimiques et histologiques sur la dégradabilité et d'autre part en termes d'application afin de proposer des solutions pour améliorer de la qualité des parois. / Maize potential value, as well as animal feed or as bioenergetics resources, is limited by the lignification of the cell wall and by the cross-linking between cell wall components. Improvement of cell wall enzymatic degradability is an important goal. In the present work we focused on the study of cell wall lignification including its establishment and the biochemical or anatomical cell wall related factors in order to investigate the impact of all these characteristics on cell wall degradability. In the first part of my work, 8 maize recombinant inbred lines were selected on the basis of their comparable lignin content and their contrasted cell wall degradability in order to assess the impact of biochemical traits on both the cell wall degradability and the plant agronomic performances independently of the main “lignin content” factor. These recombinant inbred lines and their parents were analyzed for esterified and etherified p-hydroxycinnamic acid content, for lignin content, composition and structure and for in vitro cell wall degradability. Lignin structure and esterified p-coumaric acid content were highly and significantly correlated with in vitro cell wall degradability. A multiple regression analysis showed that more than 80 % of cell wall degradability variations were explained by a regression model including two main explanatory factors: the lignin content and the estimated proportion of S lignin units esterified by p-coumaric acid. The morphological study showed that the biochemical factors limiting cell wall degradability were on the contrary favorable for ensuring agronomic performances. In the second part of my work, we studied the cell wall developmental pattern during maize internode growth. We compared the developmental pattern of 3 maize lines which presented quite similar lignin content but very different cell wall degradability at silage stage. We first characterized biochemically internodes sampled throughout plant development. Subsequently, we developed a method to quantify the variation of lignin spatial distribution within the whole stem section. At last, we completed our study of cell wall establishment by an anatomical characterization. From a temporal point of view, the different wall components were incorporated gradually during the development and three major steps were identified. From a spatial point of view, in the internode, the development of cell wall is different according to the considered region. Clearly genetic variations were observed for developmental pattern in both the two axes and were found to be associated with the variation of cell wall degradability. The results of this work were discussed firstly in terms of contribution to the understanding of cell wall lignification and of relationships between biochemical and anatomical factors with cell wall degradability variations and secondly in terms of application to propose solutions to improve cell wall quality.

Direct and large-eddy simulations of wall-bounded turbulent flows in complex geometries are presented in the thesis. To avoid the challenging resolution requirements of the near-wall region, we develop a virtual wall model in generalized curvilinear coordinates and incorporate the non-equilibrium effects via proper treatment of the momentum equations. The wall-modeled large-eddy simulation (WMLES) framework is formulated based on the wall model, accomplished via the stretched-vortex subgrid scale (SGS) model for the LES region. Based on this, we develop high-resolution in-house CFD codes, including direct numerical simulation (DNS), wall-resolved simulation (WRLES) and WMLES for wall-bounded turbulence simulations in complex geometries. First, we present LES of flow past different airfoils with Rec, based on the free-stream velocity and airfoil chord length, ranging from 104 to 2.1106. The numerical results are verified with DNS at low Rec, and validated with experimental data at higher Rec, including typical aerodynamic properties such as pressure coefficient distributions, velocity components, and also more challenging measurements such as skin-friction coefficient and Reynolds stresses. The unsteady separation behavior is investigated with skin friction portraits, which reveal a monotonic shrinking of the near wall structure scale. Second, we present LES of turbulent flow in a channel constricted by streamwise periodically distributed hill-shaped protrusions. Two Reynolds number cases, i.e. Reh=10595 and 33000 (based on the hill height and bulk mean velocity through the hill crest), are utilized to verify and validate our WMLES results. All comparisons show reasonable agreement, which enables us to further probe simulation results at higher Reynolds number (Reh=105). The Reynolds number effects are investigated, with emphasis on the mean skin-friction coefficients, separation bubble size and pressure fluctuations. The flow field at the top wall is evaluated with the empirical friction law and log-law as in planar channel flows. Finally, we present DNS of flow past the NACA0012 airfoil (Rec=104, AoA=10) with wavy roughness elements located near the leading edge. The effects of 2D surface roughness on the aerodynamic performance are investigated. For k8, massive separation occurs and almost covers the suction side of the airfoil dominating the airfoil aerodynamic performance.

All of the members of the microsporidia possess a unique, highly specialized invasion mechanism that involves the polar tube and spore wall. This chapter reviews the data on the organization, structure, and function of this invasion organelle. The application of immunological and molecular techniques and recent genome sequencing data has resulted in the identification of multiple polar tube and spore wall proteins (SWPs). The interactions of these identified proteins in the formation and function of the polar tube and spore wall remain to be determined. Inside the spore, the polar tube is filled with material and is often termed the polar filament; however, this chapter uses the term polar tube to refer to this structure when it is within the spore as well as when it forms a hollow tube after germination and is found outside the spore. The chapter presents details on the spore activation and discharge.