Modélisation de paroi et injection de turbulence pariétale pour la Simulation des Grandes Echelles des écoulements aérothermiques

Lors du développement d un nouvel avion, l estimation des échanges d énergie entre l air ambiant et les parois est une donnée cruciale pour la conception aérothermique. Cette conception repose de plus en plus sur des simulations numériques mais certains phénomènes d aérothermique externe, comme le jet débouchant du système de dégivrage des nacelles moteur, montrent les limites des modèles RANS classiques. La simulation des grandes échelles (LES) se révèle bien adaptée à ce type de phénomène mais se heurte à un coût de calcul extrêmement élevé pour ces écoulements pariétaux à très grand nombre de Reynolds. Pour lever cette limitation, cette thèse propose l étude de deux briques fondamentales : la LES avec loi de paroi (WMLES) conjuguée à l injection d une couche limite turbulente à l entrée du domaine. Pour une meilleure compréhension et une utilisation fiable de l approche loi de paroi, on se concentre tout d abord sur les sources d erreur qui lui sont associées. Après les avoir identifiées, on propose une correction de l erreur de sous-maille ainsi qu une loi de paroi adaptée aux écoulements compressibles. Grâce à ces deux éléments, on obtient une estimation correcte du flux de chaleur pariétal sur des simulations WMLES de canal plan supersonique sur parois froides. Puis, pour préparer la transition vers des applications plus industrielles, on introduit un schéma numérique plus dissipatif ce qui nous permet d étudier l influence de la méthode numérique sur l approche loi de paroi. Dans une seconde partie dédiée à l injection de couche limite pour la WMLES, on sélectionne une méthode basée sur l injection de perturbations combinée à un terme de contrôle volumique. On montre que des simulations WMLES utilisant cette méthode d injection permettent d établir une couche limite turbulente réaliste à une courte distance en aval du plan d entrée, à la fois sur une plaque plane mais également sur un écoulement de jet débouchant à la géométrie plus complexe, représentative d un cas avion.During the design of a new aircraft, the prediction of energy exchanged between the ambient air and the aircraft walls is crucial regarding aerothermal design. Numerical simulations plays a role of increasing importance in this design. However classical RANS models reach their limits on some external aerothermal flows, like the jet-in-cross-flow from the anti-icing system oh the engine nacelles. The large eddy simulation (LES) is well suited to this kind of flow but faces an extremely large computational cost for such high Reynolds number wall-bounded flows. To remove this limitation, we propose two building blocks: the Wall Modeled LES (WMLES) combined with a turbulent inflow generation. For a better understanding and a reliable use of the WMLES, we first focus on the sources of error related to this approach. We propose a correction to the subgrid-scale error as well as a wall model suitable for compressible and anisothermal flows. Thanks to these two elements, we correctly predict the wall heat flux in WMLES computations of a supersonic isothermal-wall channel flow. Then, to allow the computation of more industrial flows, we introduce some numerical dissipation and study its effect on the wall modeling approach. The last part is dedicated to turbulent inflow generation for WMLES. We select a method based on synthetic perturbation combined with a dynamic control term. We validate this method on WMLES computations of a flat plate turbulent boundary layer and a hot jet-in-cross-flow representative of an industrial configuration. In both cases, we show that a realistic turbulent boundary layer is generated at a small distance downstream from the inlet plane.TOULOUSE-INP (315552154) / SudocSudocFranceF

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Caracter\uedsticas del componente \ue9tico presente en la especializaci\uf3n en Gerencia de Programas Sociales del Decanato de Administraci\uf3n y Contadur\ueda de la Universidad Centroccidental Lisandro Alvarado

En los \ufaltimos a\uf1os, muchas universidades en el mundo se han dado a la tarea de buscar formas de profundizar su actuaci\uf3n como agentes fundamentales del Desarrollo sostenible, pues entienden que \u93las potencialidades de la Instituci\uf3n est\ue1n indisolublemente ligadas a su comunidad y su regi\uf3n\u94, y por ende comprometidas a brindar un aporte efectivo en pro del desarrollo local. Ello supone obligatoriamente integrar el componente \uc9tico como eje transversal, en el quehacer docente, de investigaci\uf3n y extensi\uf3n social de las universidades, a fin de contribuir con el incremento del capital social, el cual a su vez potencia el desarrollo sostenible. En tal sentido, y tras discernir la contribuci\uf3n que desde la especializaci\uf3n en Gerencia de Programas Sociales del Decanato de Administraci\uf3n y Contadur\ueda de la Universidad Centro Occidental Lisandro Alvarado se pueda ofrecer en beneficio del tema de la \uc9tica y el Desarrollo, con el presente trabajo se elabora un diagn\uf3stico a fin de establecer las caracter\uedsticas del componente \ue9tico presentes en la mencionada especializaci\uf3n y en base a los resultados, se plantean propuestas con el fin de adecuar las estrategias y contenidos de la especializaci\uf3n a las exigencias de los tiempos. La investigaci\uf3n se enmarca en el tipo Proyecto Factible, puesto que se limita a diagnosticar, analizar y elaborar una propuesta a partir del an\ue1lisis e interpretaci\uf3n de la realida

Taking a studio course in distributed software engineering from a large local cohort to a small global cohort

One of the challenges of global software engineering courses is to bring the practices and experience of large geographically distributed teams into the local and time-limited environment of a classroom. Over the last 6 years, an on-campus studio course for software engineering has been developed at the University of Queensland (UQ) that places small teams of students on different features of a common product. This creates two layers of collaboration, as students work within their teams on individual features, and the teams must interoperate with many other teams on the common product. The class uses continuous integration practices and predominantly asynchronous communication channels (Slack and GitHub) to facilitate this collaboration. The original goal of this design was to ensure that students would authentically experience issues associated with realistically sized software projects, and learn to apply appropriate software engineering and collaboration practices to overcome them, in a course without significant extra staffing. Data from the development logs showed that most commits take place outside synchronous class hours, and the project operates as a temporally distributed team even though the students are geographically co-located. Since 2015, a course adapted from this format has also been taught at the University of New England (UNE), an Australian regional university that is also a longstanding provider of distance education. In this course, most students study online, and the class has to be able to work globally, because as well as students taking part from around Australia, there are also typically a small number of students taking part from overseas. Transferring the course to a smaller but predominantly online institution has allowed us to evaluate the distributed nature of the course, by considering what aspects of the course needed to change to support students who are geographically distributed, and comparing how the two cohorts behave. This has produced an overall course design, to teach professional distributed software engineering practices, that is adaptable from large classes to small, and from local to global