The results from computer simulations of the gas-dynamic processes that occur during and after the rupture of diaphragms within shock tubes and expansion tubes are presented. A two-dimensional and axisymmetric finite-volume code that solves the unsteady Euler equations for inviscid compressible flow, was used to perform the simulations. The flow domains were represented as unstructured meshes of triangular cells and solution-adaptive remeshing was used to focus computational effort in regions where the flow-field gradients were high. The ability of the code to produce accurate solutions to the Euler equations was verified by examining the following test cases: supersonic vortex flow between two arcs, an ideal shock tube, and supersonic flow over a cone. The ideal shock tube problem was studied in detail, in particular the shock speed. The computed shock speed was accurate when the initial pressure ratio was low. When the initial pressure ratio was high the ow was dificult to resolve because of the large density ratio at the contact surface where significant numerical diffusion occurred. However, solution- adaptive remeshing was used to control the error and reasonable estimates for the shock speed were obtained. The code was used to perform multi-dimensional simulations of the gradual opening of a primary diaphragm within a shock tube. The development of the flow, in particular the contact surface was examined and found to be strongly dependent on the initial pressure ratio across the diaphragm. For high initial pressure ratios across the diaphragm, previous experiments have shown that the measured shock speed can exceed the shock speed predicted by one- dimensional models. The shock speeds computed via the present multi-dimensional simulation were higher than those estimated by previous one-dimensional models and were closer to the experimental measurements. This indicates that multi- dimensional ow effects were partly responsible for the relatively high shock speeds measured in the experiments. The code also has the ability to simulate two-dimensional fluid-structure interac- tions. To achieve this the Euler equations are solved for a general moving frame of reference. Mesh management during a simulation is important. This includes the ability to automatically generate a new mesh when the current mesh becomes distorted (due to the motion of the structures) and the transfer of the solution from the old mesh to the new. The shock induced rupture of thin diaphragms was examined. Previous one dimen- sional models are awed because they do not simultaneously consider the diaphragm mass and allow the upstream gas to penetrate the diaphragm mass. Two multi- dimensional models which allow the upstream gas to penetrate are described. The first model assumes the diaphragm vaporises immediately after the arrival of the incident shock. The second model assumes the diaphragm shatters into a number of pieces which can be treated as rigid bodies. The results from both models are compared with experimental data.

Η παρακάτω εργασία εκπονήθηκε κατά την διάρκεια του ακαδημαϊκού έτους 2008-2009 και πρόκειται για μια πτυχιακή εργασία που αφορά τα υπόγεια τεχνικά έργα και συγκεκριμένα την σήραγγα Αιγίου. Η σήραγγα Αιγίου εντάσσεται στο τμήμα από Χ.Θ. 75 + 000 έως Χ.Θ. 90 + 000 της νέας σιδηροδρομικής γραμμής Κορίνθου – Πατρών, η οποία είναι διπλής κατεύθυνσης και αναπτύσσεται στην ευρύτερη περιοχή της πόλεως του Αιγίου. Ειδικότερα, η υπόγεια χάραξη της νέας σιδηροδρομικής γραμμής διέρχεται αρχικά την κατοικημένη περιοχή «Κουλούρα» και παρακάμπτοντας την πόλη του Αιγίου καταλήγει στην περιοχή του εργοστασίου «Κουνινιώτης». Στόχος της παρούσας εργασίας είναι να παρουσιαστούν όλα τα στάδια της μελέτης και της διάνοιξης της σήραγγας τα οποία εντάσσονται στο πλαίσιο της εργασίας του Γεωλόγου σε αυτήν, ώστε να δοθεί μια πλήρης εικόνα σχετικά με τις τεχνικογεωλογικές συνθήκες διάνοιξης της σήραγγας. / The work below was elaborated during the academicals years 2008-2009 and is about a certificated work which is related to the underground technical works and concretely the tunnel in Egio. The tunnel in Egio is enlisted from the kilometrical part 75 +000 to the kilometrical part 90 + 000 of the new railway Korinthou-Patras, which has double direction and is developed in the city of Egio. Specifically the underground incision of the new railway goes through the area “Kouloura” and avoiding the city of Egio ends in the area of “Kouniniotis factory”. The purpose of this work is to present all the stages of the study and the opening of the tunnel which are enlisted in the Geologist’s work, so as to be given a full image in relation to the engineering geological conditions of the opening of the tunnel.

Σκοπός της παρούσας διατριβής είναι η παρουσίαση και μελέτη των τεχνικογεωλογικών συνθηκών κατά τη διάνοιξη των σηράγγων Πλάτανου και Τράπεζας της Σ.Γ.Υ.Τ. Κιάτου – Αίγιου, ενώ δίνεται έμφαση στο τμήμα της εισόδου της σήραγγας Πλατάνου που βρίσκεται εντός ζώνης ενεργής κατολίσθησης. Ειδικότερα γίνεται εκτενής ανάλυση στο συστηματικά οργανωμένο πρόγραμμα γεωτεχνικής και δομητικής παρακολούθησης της κατασκευής, που περιλαμβάνει : 1. Αυτοματοποιημένο Σύστημα Παρακολούθησης 2. Χωροσταθμικές Ακίδες 3. Οπτικοί στόχοι εντός σήραγγας 4. Εκτασιόμετρα 3 ράβδων 5. Κλισιόμετρα 6. Κύτταρα φορτίου αγκυρίου 7. Πιεζόμετρα Η εγκατάσταση των παραπάνω οργάνων αποσκοπεί στη διενέργεια μετρήσεων υψηλής ακρίβειας, ώστε να είναι δυνατή η έγκυρη και έγκαιρη εξαγωγή συμπερασμάτων σχετικά με την επάρκεια και την αποτελεσματικότητα των μέτρων προσωρινής υποστήριξης. Με βάση την επεξεργασία των στοιχείων, που συγκεντρώθηκαν από τη διάνοιξη του συνολικού μήκους της σήραγγας Πλατάνου στο τμήμα της εισόδου αυτής (περίπου 300μ από την είσοδο αυτής, εντός της ζώνης κατολίσθησης), όπου και εφαρμόστηκαν οι προσαρμοσμένες κατηγορίες εκσκαφής και σύμφωνα με τις επί τόπου μετρήσεις, επιτεύχθηκαν οι ακόλουθοι κύριοι στόχοι: • Αποφυγή ανάπτυξης υψηλών συγκλίσεων στο κέλυφος της προσωρινής. • Περιορισμός των επιφανειακών καθιζήσεων στο οικισμό άνωθεν της σήραγγας. • Προπορεία της εκσκαφής της άνω ημιδιατομής και αξιολόγηση της συμπεριφοράς της βραχόμαζας και της αποτελεσματικότητας των μέτρων υποστήριξης, ώστε εφόσον απαιτηθεί να υπάρχει δυνατότητα έγκαιρης τροποποίησης των μέτρων υποστήριξης της Β’ φάσης. • Ανάσχεση προβλημάτων επάρκειας των κατηγοριών εκσκαφής της οριστικής μελέτης καθώς και οριακών συντελεστών ασφαλείας. / The purpose of this thesis is the presentation and study of technical geological conditions during the opening of tunnels of Platanos and Trapezas of the high speed railway Kiato - Aigion, emphasizing on the entrance of the tunnel Platanos located within an active landslide zone. In particular, extensive analysis is given to the systematically organized program of geotechnical and construction monitoring of building activity, including: 1. Automated Monitoring System 2. Space determining Spikes 3. Optical targets in the tunnel 4. Ektasiometra 3 bars 5. Gradiometers 6. Anchor load cells 7. Piezometer The installation of these instruments is designed to perform high precision measurements in order to obtain accurate and timely conclusions on the adequacy and effectiveness of the tunnel’s temporary support. Based on data processing, collected from the opening of the total length of the tunnel Platanos in this part of the entrance (about 300m from the entrance within the landslide zone), where custom excavation categories were applied according to the in situ measurements, obtained the following main objectives: • Avoid high growth convergence in temporary support. • Reduction of surface subsidence in the village above the tunnel. • Advance the excavation of the upper semi section and evaluation of rock mass behavior and the effectiveness of support measures, in order if necessary to be able to timely amend the measures to support the second phase. • Averting adequacy problems of digging categories of the final design and marginal safety factors.

Este estudo objetiva a sistematização do conhecimento, através de uma abordagem multidisciplinar, de forma a conformar uma proposta inicial de protocolo de gestão ocupacional e ambiental em grandes túneis urbanos em âmbito nacional. Há na presente pesquisa uma atenção particular aos túneis urbanos dedicados ao tráfego de veículos automotores, devido às suas características físico-espaciais que os tornam especialmente perigosos e tóxicos aos seus usuários e aos funcionários envolvidos. A relativa carência de material bibliográfico de caráter sistêmico e específico no Brasil enseja à busca por referências em documentos desenvolvidos em outros países. Ainda que em nível preliminar, a compilação crítica de dados, normas e referências pesquisadas, à luz do contexto e dos instrumentos normativos brasileiros referentes ao tema, traduz-se no aspecto original desta proposta dissertativa, a ser possivelmente utilizada como ponto de partida para estudos mais extensos. São abordadas as seguintes disciplinas relativas ao objeto de pesquisa: a) Características físico-espaciais; b) Formas de uso; c) Sistema de ventilação e exaustão; d) Sistema de iluminação; e) Sistema de segurança contra sinistros e incêndio; f) Sistema de fiscalização e orientação de tráfego, comunicação e sinalização; g) Sistema de drenagem; h) Sistema de gerenciamento de resíduos sólidos. O túnel Rebouças (1962-1965) e o túnel Engenheiro Raymundo de Paula Soares (Linha Amarela) (1997), distanciados por mais de três décadas, foram escolhidos como estudos de caso, não tão somente devido aos seus portes, fluxos intensos de veículos etc., mas também devido aos contextos das evoluções normativas em que se inserem. / Aiming to establish an initial proposal for an environmental and operational management protocol for large urban tunnels, one that could be applied nationwide, this study also intends to systematize, through a multidisciplinary approach, the state of the art on the subject. In this survey it will be given particular attention to vehicular urban tunnels. Due to its physical and spatial characteristics they are especially dangerous and toxic to both their users and employees involved in maintenance. Given the lack of systematic and specific bibliographic material in Brazil it was necessary to inquire about references, studies and investigations developed in other countries. A critical compilation of such data, standards and benchmarks, while in its initial level, considering the Brazilian context and the actual legal instruments, may reflect the original feature of this essay. It is hoped that the results can be used as a starting point for other extensive studies. Considering the main focus of this research, the following topics are discussed: a) physical and spatial characteristics; b) usage and operation; c) ventilation and exhaust system; d) lighting system; e) accidents prevention, security and fire protection system; f) management, traffic supervision, communication and signaling system; g) drainage system; h) solid waste management system. The two tunnels, Rebouças (1962-1965) and Engenheiro Raymundo de Paula Soares (Linha Amarela) (1997), both located in Rio de Janeiro and more than three decades apart, were selected as case studies, not only Because of their size, intensity of flows etc., but also because of the changing normative contexts in which they operate.

Rock groundwater has always caused major problems when tunnelling. Water leaking into tunnels can cause large problems, not only on the construction itself but also on the environment. A continuous water leakage can lead to a declining water supply, and geotechnical problems can occur as subsidence in the ground. Therefore it is of great importance to predict the consequences that can appear in the surroundings due to a declining groundwater surface. The aim of the study was to investigate different methods for predicting leakage and changes in groundwater level due to tunnelling excavations in rock. This thesis was performed by comparing mathematical methods, actual groundwater changes and results from preliminary investigations. Investigations were made for three railway tunnels planned by Botniabanan AB. Varvsbergstunneln (2 km), Åsbergstunneln (1 km) and Strannebergstunneln (1.4 km) all situated in the surroundings of Örnsköldsvik. During the time this thesis was performed, all tunnels have been fully excavated. This thesis has emphasised difficulties in predicting groundwater behaviour as tunnelling excavations are made in rocks. The reason is the complex characteristics of rocks. The conductivity seems to be the parameter that is most difficult to determine with a high accuracy, and hence the accuracy shows in the results. Also the result is affected by the chosen mathematical method. Although careful preliminary investigations are made, it is hard to determine the rock characteristics with such accuracy that leakage and groundwater level changes can be predicted with high precision. However, mathematical methods are a good supplement when determining groundwater influences around railway tunnels in rock. / Vatten i berg har ofta inneburit stora problem vid tunnelbyggen. Vatten som läcker in i tunnlar kan orsaka stora problem på såväl konstruktionen som miljön och dessutom kan ett stort inflöde medföra stabilitetsproblem. Om vatten läcker in kontinuerligt kan omgivningarna dräneras så att vattentillgången minskar och geotekniska problem kan uppstå i form av sättningar i marken. Det är därför av stor vikt att prediktera inläckaget och de konsekvenser som kan uppstå på omgivningen till följd av en grundvattensänkning. Syftet med arbetet har varit att undersöka olika metoder för att förutspå inläckage och nivåförändring av grundvatten i samband med tunnelbygge i berggrund. Arbetet utfördes genom att en jämförelse gjordes mellan matematiska metoder, verkliga grundvattenförändringar samt resultat från förundersökningar. Undersökningar gjordes för tre järnvägstunnlar som är projekterade av Botniabanan AB. Varvsbergstunneln (2 km), Åsbergstunneln (1 km) samt Strannebergstunneln (1.4 km) som alla är belägna i närheten av Örnsköldsvik. Under examensarbetets gång har man hunnit driva igenom samtliga tre tunnlar. Examensarbetet har påvisat svårigheterna i att förutspå grundvattnets beteende vid tunnelbyggen i berggrund. Detta beror på att berggrunden är ett komplext byggnadsmaterial vars egenskaper är svåra att bestämma. Konduktiviteten tycks vara den parameter som är svårast att bestämma med hög noggrannhet, och noggrannheten avspeglas i resultatet. Dessutom beror resultatet av vilken beräkningsmetod som väljs. Trots utförliga förundersökningar är det alltså svårt att bestämma bergets egenskaper med sådan noggrannhet att inläckage och nivåförändring av grundvatten kan förutspås med stor precision. Dock är matematiska metoder bra hjälpmedel för att bestämma grundvattenpåverkan kring järnvägstunnlar i berg.

Os sistemas de classificação maciços rochosos e as redes neurais artificiais possuem diversas similaridades. Existem características que estão presentes nos dois tipos de sistemas: bases de dados são usadas para o seu desenvolvimento; e pesos são parte da representação do conhecimento. Os principais sistemas de classificação geomecânicas (Sistema Q e RMR) podem ser escritos como representações neurais locais. Tais representações permitem uma melhor compreensão do processo de classificação e identificação de padrões realizado pelas classificações convencionais. Experimentos convencionais foram realizados com modelos de redes neurais não-supervisionados. Os modelos não supervisionados permitiriam uma melhor compreensão da distribuição dos dados no espaço de feições. Um modelo supervisionado para escavações subterrâneas em todo domínio do espaço de feições. Importantes relações entre características foram encontradas. / Rock mass classification systems and artificial neural networks have several similarities. There is some characteristics present in both systems: data bases are used in they development, and weights are part of the knowledge representation. The main rock mass classification systems (Q-system and RMR) can be written as local neural network representations. This representation helps a better understanding of the pattern classification and identification process made by the conventional classifications. Computational experiments were made with unsupervised and supervised neural networks models. Unsupervised models allow a better understanding of the data in the feature space. A supervised model allow to make a mapping of the support type used in underground excavation in all feature space domain. Important relations between domain regions characteristics and type of support used were found.

O presente trabalho aborda o estudo do comportamento de túneis em maciços de solo. É dada ênfase na aplicação de análises numéricas com emprego de diferentes modelos constitutivos elasto-plásticos para solos. São apresentadas análises numéricas tridimensionais de um túnel amplamente instrumentado pertencente à Companhia do Metropolitano de São Paulo. As análises são realizadas com auxílio de um programa computacional de elementos finitos. O comportamento do maciço em pontos situados ao redor da escavação é minuciosamente estudado e a capacidade dos modelos em representar adequadamente o comportamento verificado na obra pelas instrumentações é avaliada. Além das análises numéricas o trabalho aborda os principais conceitos relacionados com escavações de túneis em maciços de solo. Conceitos relacionados com a engenharia prática de túneis são apresentados de maneira qualitativa, sem formulações teóricas e matemáticas. Uma revisão bibliográfica com publicações recentes das principais revistas e periódicos que tratam do tema de análise numérica aplicada a túneis é apresentada. O trabalho também apresenta uma revisão dos principais conceitos relacionados com os modelos constitutivos comumente utilizados para análise de problemas de geotecnia. Além do modelo elástico são apresentados os modelos elasto-plásticos de Tresca, von Misses, Drucker-Prager e Mohr-Coulomb. Uma breve introdução aos conceitos básicos de estado crítico, juntamente com as equações do modelo Cam-Clay original e Cam-Clay modificado são apresentadas. Antes da apresentação das equações desses modelos constitutivos, são introduzidos os conceitos básicos relacionados com o comportamento dos materiais elasto-plásticos. Os conceitos de material elástico perfeitamente plástico e de material com endurecimento (ou hardening) e amolecimento (ou softening) são apresentados. Os conceitos de superfície de plastificação e de superfície de potencial plástico também são apresentados. Por fim, são sintetizados os pontos mais relevantes da pesquisa realizada, apontando as limitações do trabalho com sugestões de novos estudos a serem realizados nessa mesma linha de pesquisa. / The present research approaches the study of the behaviour of tunnels in soil. It is given emphasis in the application of numerical analyses using different elasto-plastic constitutive models for soils. Three-dimensional numerical analyses of a widely instrumented tunnel belonging to the Company of the Metropolitan of São Paulo are presented. The analyses are carried through with aid of a computational program of finite elements. The behaviour of the soil mass in points located around the excavation is thoroughly studied and the capacity of the models in adequately representing the field behavior verified by the instrumentations is evaluated. Furthermore, the work approaches the main concepts related to tunneling in soils. Concepts related to practical engineering of tunnels are presented in a qualitative way, without theoretical and mathematical formulations. A literature review of recent publications of the most important periodic magazines and that deal with the subject of numerical analysis applied to tunnels is presented. The work also presents a revision of the main concepts related to the constitutive models normally used for analysis of geotechnical problems. Beyond the elastic model the elasto-plastics models of Tresca, von Misses, Drucker-Prager and Mohr-Coulomb are presented. Brief introductions to the basic concepts of critical state, together with the equations of the (original) Cam-Clay original and (modified) Cam-Clay modified models are presented. Before the presentation of the equations of these constitutive models, the basic concepts of the behaviour of the elasto-plastics materials are introduced. The concepts of perfectly plastic elastic material and material with hardening and softening are presented. The concepts of plastic surface and plastic potencial surface are also presented. Finally, the most relevant points of the research are synthesized, pointing the limitations of the developed work along with suggestions for new studies to be carried through in this line of research.

O processo de liberação da operação comercial de um túnel rodoviário, sempre é realizada sobre a pressão típica do final de um cronograma, cujo prazo final, está em vias de se esgotar. Por outro lado considerando os relevantes riscos envolvidos com a operação de um túnel, o órgão público que libera o início da operação comercial (Artesp no caso do Estado de São Paulo), deve ter plena certeza que a nova estrutura está pronta a utilização e apresenta-se totalmente preparada a atender os requisitos mínimos de segurança. O presente trabalho propõe uma metodologia de avaliação de conformidade aderente a NBR ISO/IEC 17020:2006 - avaliação de conformidade com os critérios gerais para o funcionamento de diferentes tipos de organismos que executam inspeções. Para tanto foi realizado um extenso e minucioso trabalho de identificação dos requisitos aplicáveis, concatenando as referências internacionais de túneis, o modus operandi nacional e a ferramenta gerenciamento de riscos, que resultaram numa proposta de metodologia de avaliação de conformidade composta por onze atividades, que aplicadas permitem avaliar as condições de liberação ao uso e operação comercial de túneis rodoviários. / The process of releasing the commercial operation of a road tunnel is always done under the typical pressure of a chronogram deadline. On the other hand, considering the relevant risks involved with the tunnel operation, the public institution that releases the beginning of the commercial operation (ARTESP, in the case of São Paulo State), should be totally sure that the new structure is ready to be used and shows it is completely prepared to meet the needs of the minimum security requirements. The present work proposes an evaluation methodology of adherent conformity the NBR ISO/IEC 17020:2006 Conformity evaluation with the general criteria for the functioning of different types of organisms that perform inspections. In order to do so, a large and detailed work of identification of the applicable requirements, linking together the international references of tunnels, national way of working and the tool Management of Risks, that ended in a proposal of conformity evaluation methodology composed by eleven activities, that if applied, allow evaluation of the releasing conditions to the use and commercial operation of road tunnels.

Recently, the wavy leading edge airfoils, inspired by the humpback whale´s flipper, have been investigated, as flow control mechanisms, at low Reynolds numbers in order to improve aerodynamic performance in this particular flow regime. The overall aim of this work is to investigate the airfoil geometric effects on wavy leading edge phenomena in the low Reynolds number regime. Experimental investigations were carried out correlating force measurements with mini-tuft and oil visualizations in order to understand the airfoil thickness effects on wavy leading edge phenomena. Three sets of airfoil thickness were tested (NACA 0012, NACA 0020 and NACA 0030), each set consisting of smooth plus three wavy configurations (A=0.11c, ?=0.40c; A=0.03c, ?=0.40c and A=0.03c, ?=0.11c); Reynolds number was varied between 50,000 and 290,000. The results present many findings that were not possible in previous studies due the fact that these investigations were constrained to specific geometries and/or flow conditions. At higher Reynolds number, the decrease in airfoil thickness leads the airfoils to leading edge stall characteristics causing the lowest aerodynamic deterioration for the thinnest wavy airfoil as compared to smooth configuration in the pre-stall regime. In addition, the results show impressive tubercle performance in the lowest Reynolds number. For any tubercle geometry and airfoil thickness, the wavy leading edge airfoils present higher maximum lift values as compared to smooth configurations showing an unprecedented increase in performance for a full-span model tested in the literature. The flow visualizations present two flow mechanisms triggered by secondary flow: three-dimensional laminar separation bubbles and vortical structures. Regarding three-dimensional laminar bubbles, the results confirm some of the few previous experimental and numerical studies, and presents for the first time these structures as a very efficient flow control mechanism in the post-stall regime justifying the impressive increase in maximum lift in the lowest Reynolds number. Besides that, two characteristics of laminar bubbles, \"tipped-bubbles\" and \"elongated-bubbles\", are identified with different effects in the pre-stall regime. This thesis presents higher tubercle performance for thinner airfoils (NACA 0012) and/or lower Reynolds number conditions (Re=50,000) showing clearly that an optimum performance lead the \"tubercles\" to operate under conditions of leading edge flow separation conditions. Therefore, a design space for tubercles conducted to leading edge stall characteristics confirming the hypothesis of Stanway (2008) eight years before. / Recentemente, aerofólios com bordo de ataque ondulados, inspirados na nadadeira da baleia jubarte, tem sido investigados como mecanismo de controle de escoamento para baixo número de Reynolds com a finalidade de se aumentar o desempenho aerodinâmico neste específico regime de escoamento. O objetivo geral deste trabalho é investigar os efeitos geométricos do aerofólio nos fenômenos do bordo de ataque ondulado na condição de baixo número de Reynolds. Investigações experimentais foram realizadas correlacionando medições de forças com visualizações de lã e óleo a fim de compreender os efeitos da espessura do aerofólio sobre os fenômenos de bordo de ataque ondulado. Três conjuntos de espessura de aerofólios foram testados (NACA 0012, NACA 0020 e NACA 0030) na faixa de número de Reynolds entre 50,000 e 290,000, onde cada conjunto tem um aerofólio liso e três ondulados (A = 0.11c, ? = 0.40c; A = 0.03c, ? = 0.40c e A = 0.03c, 0.11c ? =0.11c). O dados experimentais mostram importantes resultados que não foram possíveis em estudos anteriores devido às investigações serem restritas à geometria ou/e condição de escoamento específicas. O resultados de medida de força mostram que a diminuição da espessura do aerofólio conduz às características de separação de escoamento de bordo de ataque que causam menor deterioração aerodinâmica nos aerofólios ondulados finos quando comparados aos lisos no regime de pré-stall. Além disso, os resultados mostram um desempenho destacado do bordo de ataque ondulado para condição de menor número de Reynolds. Em quaisquer espessuras de aerofólio, os bordos ondulados apresentam valores de sustentação máxima maiores quando comparado aos aerofólios lisos mostrando assim resultado inédito na literatura para modelos ondulados bi-dimensionais. As visualizações de óleo evidenciaram dois mecanismos de controle de escoamento desencadeadas pelo escoamento secundário: bolhas de separação laminar tridimensionais e estruturas vorticais. Os resultados confirmam alguns poucos estudos experimentais e numéricos anteriores relacionadas com bolhas tridimensionais, e apresenta pela primeira vez estas estruturas como um mecanismo muito eficiente de controle de escoamento em regime de pós-stall justificando o aumento de máxima sustentação para o menor número de Reynolds. Adicionalmente, foram identificadas duas estruturas de bolhas tridimensionais nomeados aqui como \"bolhas com pontas\" e \"bolhas alongadas\" que causam distintos efeitos no regime de pré-stall. Esta tese apresenta como resultado maior desempenho para aerofólios ondulados com menor espessura (NACA 0012) e/ou para condições de menor número de Reynolds (Re=50,000)mostrando claramente que estas características levam as ondulações a operarem em condições de stall de bordo de ataque assim tendo um desempenho superior. Portanto, um espaço de projeto para tubérculos conduz às características de stall de bordo de ataque confirmando a suposição de Stanway (2008) oitos anos antes.

<p>Most of the attention to the seismic performance of tunnels has been devoted to shear waves propagating in a direction perpendicular to the tunnel axis, with motion perpendicular to the tunnel axis, causing the so-called “ovaling or racking response”. Body waves, however, can travel through the ground and intersect the tunnel at different angles, thus inducing a complex seismic response that requires a comprehensive understanding of all modes of deformation. This study provides analytical solutions to capture the behavior of the liner and the surrounding ground, for a deep circular tunnel subjected to body waves, for all five possible modes of deformation: (i) axial compression-extension; (ii) transverse compression-extension; (iii) ovaling; (iv) axial shear; and (v) axial bending or snaking. The main assumptions used to derive the analytical solutions include: (i) the tunnel is deep and very long and has a circular cross section; (ii) the ground and the support are homogeneous and isotropic, and their response remains elastic; (iii) the interface between the ground and the liner is either no-slip or full-slip; (iv) the pseudo-static approach, i.e. inertia forces can be neglected, is acceptable to estimate seismic deformations; (v) for the transverse compression-extension and ovaling deformation modes, plane strain conditions in the direction of the tunnel axis apply at any cross section; and (vi) for the axial compression-extension and axial bending deformation modes, the wavelength of the seismic motions is much larger than the tunnel radius. Two and three-dimensional numerical simulations with the finite element codes ABAQUS, for static drained/undrained loading and dynamic drained loading conditions, and MIDAS GTS NX, for dynamic undrained loading conditions, are carried out to validate the analytical solutions and further investigate the seismic response of the tunnel. All the comparison results show good agreement between the analytical and numerical solutions.</p> <p>Dynamic amplification effects on the tunnel cross section are studied for the axial compression-extension, transverse compression-extension, and axial bending deformation modes, through a set of dynamic time-history models where the input frequency of the far-field seismic motion is changed. The results reveal the limits of the analytical solutions, in the form of minimum wavelength-to-tunnel diameter (/D) ratios such that the errors are less than twenty percent, including: (i) 25 (drained) and 20 (undrained) for axial compression-extension; (ii) 25 (drained) and 12.5 (undrained) for transverse compression- extension; and (iii) 7.5 (unsupported tunnel), 7.5 (supported tunnel with no-slip interface), and 12.5 (supported tunnel with full-slip interface) for axial bending or snaking. These ratios are also the limits of applicability of quasi-static (instead of dynamic) numerical simulations to estimate the seismic behavior of the liner and the surrounding ground.</p>