Variational multiscale stabilization of finite and spectral elements for dry and moist atmospheric problems

In this thesis the finite and spectral element methods (FEM and SEM, respectively) applied to problems in atmospheric simulations are explored through the common thread of Variational Multiscale Stabilization (VMS). This effort is justified by three main reasons. (i) the recognized need for new solvers that can efficiently execute on massively parallel architectures ¿a spreading framework in most fields of computational physics in which numerical weather prediction (NWP) occupies a prominent position. Element-based methods (e.g. FEM, SEM, discontinuous Galerkin) have important advantages in parallel code development; (ii) the inherent flexibility of these methods with respect to the geometry of the grid makes them a great candidate for dynamically adaptive atmospheric codes; and (iii) the localized diffusion provided by VMS represents an improvement in the accurate solution of multi-physics problems where artificial diffusion may fail. Its application to atmospheric simulations is a novel approach within a field of research that is still open. First, FEM and VMS are described and derived for the solution of stratified low Mach number flows in the context of dry atmospheric dynamics. The validity of the method to simulate stratified flows is assessed using standard two- and three-dimensional benchmarks accepted by NWP practitioners. The problems include thermal and gravity driven simulations. It will be shown that stability is retained in the regimes of interest and a numerical comparison against results from the the literature will be discussed. Second, the ability of VMS to stabilize the FEM solution of advection-dominated problems (i.e. Euler and transport equations) is taken further by the implementation of VMS as a stabilizing tool for high-order spectral elements with advection-diffusion problems. To the author¿s knowledge, this is an original contribution to the literature of high order spectral elements involved with transport in the atmosphere. The problem of monotonicity-preserving high order methods is addressed by combining VMS-stabilized SEM with a discontinuity capturing technique. This is an alternative to classical filters to treat the Gibbs oscillations that characterize high-order schemes. To conclude, a microphysics scheme is implemented within the finite element Euler solver, as a first step toward realistic atmospheric simulations. Kessler microphysics is used to simulate the formation of warm, precipitating clouds. This last part combines the solution of the Euler equations for stratified flows with the solution of a system of transport equations for three classes of water: water vapor, cloud water, and rain. The method is verified using idealized two- and three-dimensional storm simulations.En esta tesis los métodos de elementos finitos y espectrales (FEM - finite element method y SEM- spectral element method, respectivamente), aplicados a los problemas de simulaciones atmosféricas, se exploran a través del método de estabilización conocidocomo Variational Multiscale Stabilization (VMS). Tres razones fundamentales justifican este esfuerzo: (i) la necesidad de tener nuevos métodos de solución de las ecuaciones diferenciales a las derivadas parciales usando máquinas paralelas de gran escala –un entorno en expansión en muchos campos de la mecánica computacional, dentro de la cual la predicción numérica de la dinámica atmosférica (NWP-numerical weather prediction)representa una aplicación importante. Métodos del tipo basado en elementos(por ejemplo, FEM, SEM, Galerkin discontinuo) presentan grandes ventajas en el desarrollo de códigos paralelos; (ii) la flexibilidad intrínseca de tales métodos respecto a lageometría de la malla computacional hace que esos métodos sean los candidatos ideales para códigos atmosféricos con mallas adaptativas; y (iii) la difusión localizada que VMSintroduce representa una mejora en las soluciones de problemas con física compleja en los cuales la difusión artificial clásica no funcionaría. La aplicación de FEM o SEM con VMS a problemas de simulaciones atmosféricas es una estrategia innovadora en un campo de investigación abierto. En primera instancia, FEM y VMS vienen descritos y derivados para la solución de flujos estratificados a bajo número de Mach en el contexto de la dinámica atmosférica. La validez del método para simular flujos estratificados es verificada por medio de test estándar aceptado por la comunidad dentro del campo deNWP. Los test incluyen simulaciones de flujos térmicos con efectos de gravedad. Se demostrará que la estabilidad del método numérico se preserva dentro de los regímenesde interés y se discutirá una comparación numérica de los resultados frente a aquellos hallados en la literatura. En segunda instancia, la capacidad de VMS para estabilizarmétodos FEM en problemas de advección dominante (i.e. ecuaciones de Euler y ecuaciones de transporte) se implementa además en la solución a elementos espectrales de alto orden en problemas de advección-difusión. Hasta donde el autor sabe, esta es una contribución original a la literatura de métodos basados en elementos espectrales en problemas de transporte atmosférico. El problema de monotonicidad con métodos de alto orden es tratado mediante la combinación de SEM+VMS con una técnica de shockcapturing para un mejor tratamiento de las discontinuidades. Esta es una alternativa a los filtros que normalmente se aplican a SEM para eilminar las oscilaciones de Gibbsque caracterizan las soluciones de alto orden. Como último punto, se implementa un esquema de humedad acoplado con el núcleo en elementos finitos; este es un primer paso hacia simulaciones atmosféricas más realistas. La microfísica de Kessler se emplea para simular la formación de nubes y tormentas cálidas (warm clouds: no permite la formación de hielo). Esta última parte combina la solución de las ecuaciones de Eulerpara atmósferas estratificadas con la solución de un sistema de ecuaciones de transporte de tres estados de agua: vapor, nubes y lluvia. La calidad del método es verificadautilizando simulaciones de tormenta en dos y tres dimensiones

The Impacts of Dry Dynamic Cores on Asymmetric Hurricane Intensification

The article of record as published may be found at http://dx.doi.org/10.1175/JAS-D-16-0055.1The fundamental pathways for tropical cyclone (TC) intensification are explored by considering axisym- metric and asymmetric impulsive thermal perturbations to balanced, TC-like vortices using the dynamic cores of three different nonlinear numerical models. Attempts at reproducing the results of previous work, which used the community WRF Model, revealed a discrepancy with the impacts of purely asymmetric thermal forcing. The current study finds that thermal asymmetries can have an important, largely positive role on the vortex intensification, whereas other studies find that asymmetric impacts are negligible. Analysis of the spectral energetics of each numerical model indicates that the vortex response to asym- metric thermal perturbations is significantly damped in WRF relative to the other models. Spectral kinetic energy budgets show that this anomalous damping is primarily due to the increased removal of kinetic energy from the vertical divergence of the vertical pressure flux, which is related to the flux of inertia–gravity wave energy. The increased kinetic energy in the other two models is shown to originate around the scales of the heating and propagate upscale with time from nonlinear effects. For very large thermal amplitudes (50 K), the anomalous removal of kinetic energy due to inertia–gravity wave activity is much smaller, resulting in good agreement between models. The results of this paper indicate that the numerical treatment of small-scale processes that project strongly onto inertia–gravity wave energy can lead to significant differences in asymmetric TC intensification. Sensitivity tests with different time integration schemes suggest that diffusion entering into the implicit solution procedure is partly responsible for the anomalous damping of energy.Institute of Geophysics, Planetary Physics and Signatures (IGPPS) at Los Alamos National LaboratoryOffice of Naval Research through program element PE-0602435Institute of Geophysics, Planetary Physics and Signatures (IGPPS) at Los Alamos National LaboratoryOffice of Naval Research through program element PE-060243

دیدگاه کارورزان، دستیاران و اعضای هیأت علمی بخش زنان در خصوص عوامل مؤثر بر شکل‌گیری اخلاق حرفه‌ای در بالین

مقدمه: آموزش اخلاق حرفه­ای بخش مهمی از برنامه­های فراگیران پزشکی است و حرفه ای‌گری (پروفیشنالیسم) از شایستگی­های محوری دوره پزشکی محسوب می­شود. شناسایی عوامل مؤثر بر فراگیری حرفه ای‌گری در بخش زنان و زایمان که از چالش­های اخلاقی خاص خود برخوردار است، می­تواند به کارآمدی برنامه­های آموزشی کمک کند. مطالعه حاضر با هدف تبیین دیدگاه و تجربیات اساتید و فراگیران پزشکی در بخش زنان و زایمان در خصوص عوامل مؤثر بر شکل‌گیری اخلاق حرفه­ای در بالین انجام شد. روش‌کار: در این مطالعه کیفی (1392)، 10 نفر از اساتید زنان و زایمان و 30 نفر از دستیاران تخصصی و کارورزان بخش زنان و زایمان مرکز آموزشی درمانی شهید صیاد شیرازی مشارکت نمودند. برای جمع‌آوری داده‌ها از روش مصاحبه­های انفرادی نیمه‌ساختار تا رسیدن به اشباع داده­ها استفاده شد. مصاحبه­ها خط به خط، دست‌نویس و مطابق رویکرد "تحلیل محتوای مرسوم" کدگذاری و طبقه‌بندی شدند. یافته‌ها: از تحلیل داده­ها چهار مضمون اصلی"ماهیت انسانی کار، شخصیت و منش فردی، داشتن الگو و مدل و عوامل آموزشی اجتماعی" استخراج شد که تبیین کننده عوامل مؤثر بر شکل‌گیری اخلاق حرفه­ای در بخش زنان و زایمان از دیدگاه اساتید و دانشجویان و دستیاران پزشکی بود. نتیجه‌گیری: الگو بودن اساتید و برنامه­های آموزشی بالینی در بخش زنان و زایمان، از مهم‌ترین عوامل مؤثر بر شکل‌گیری اخلاق حرفه­ای است، لذا به نظر می­رسد با مداخلات آموزشی مناسب روی این دو مؤلفه مهم بتوان به ارتقاء آموزش اخلاق حرفه­ای در بالین کمک کرد. کلیدواژه ها آموزش اخلاق؛ اخلاق حرفه‌ای؛ برنامه­های دستیاری؛ حرفه‌ ای گری؛ زنان و زایمان؛ کارورز پزشکی عنوان مقاله [English

A Review of Element-Based Galerkin Methods for Numerical Weather Prediction: Finite Elements, Spectral Elements, and Discontinuous Galerkin

Numerical weather prediction (NWP) is in a period of transition. As resolutions increase, global models are moving towards fully nonhydrostatic dynamical cores, with the local and global models using the same governing equations; therefore we have reached a point where it will be necessary to use a single model for both applications. The new dynamical cores at the heart of these unified models are designed to scale efficiently on clusters with hundreds of thousands or even millions of CPU cores and GPUs. Operational and research NWP codes currently use a wide range of numerical methods: finite differences, spectral transform, finite volumes and, increasingly, finite/spectral elements and discontinuous Galerkin, which constitute element-based Galerkin (EBG) methods.Due to their important role in this transition, will EBGs be the dominant power behind NWP in the next 10 years, or will they just be one of many methods to choose from? One decade after the review of numerical methods for atmospheric modeling by Steppeler et al. (Meteorol Atmos Phys 82:287–301, 2003), this review discusses EBG methods as a viable numerical approach for the next-generation NWP models. One well-known weakness of EBG methods is the generation of unphysical oscillations in advection-dominated flows; special attention is hence devoted to dissipation-based stabilization methods. Since EBGs are geometrically flexible and allow both conforming and non-conforming meshes, as well as grid adaptivity, this review is concluded with a short overview of how mesh generation and dynamic mesh refinement are becoming as important for atmospheric modeling as they have been for engineering applications for many years.The authors would like to thank Prof. Eugenio Oñate (U. Politècnica de Catalunya) for his invitation to submit this review article. They are also thankful to Prof. Dale Durran (U. Washington), Dr. Tommaso Benacchio (Met Office), and Dr. Matias Avila (BSC-CNS) for their comments and corrections, as well as insightful discussion with Sam Watson, Consulting Software Engineer (Exa Corp.) Most of the contribution to this article by the first author stems from his Ph.D. thesis carried out at the Barcelona Supercomputing Center (BSCCNS) and Universitat Politècnica de Catalunya, Spain, supported by a BSC-CNS student grant, by Iberdrola Energías Renovables, and by grant N62909-09-1-4083 of the Office of Naval Research Global. At NPS, SM, AM, MK, and FXG were supported by the Office of Naval Research through program element PE-0602435N, the Air Force Office of Scientific Research through the Computational Mathematics program, and the National Science Foundation (Division of Mathematical Sciences) through program element 121670. The scalability studies of the atmospheric model NUMA that are presented in this paper used resources of the Argonne Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract DE-AC02-06CH11357. SM, MK, and AM are grateful to the National Research Council of the National Academies.Peer ReviewedPostprint (author's final draft

Desarrollo de la competencia transversal “Tercera Lengua” – aplicación a proyectos de ingeniería aeronáutica

La docencia que suele impartirse en las asignaturas de Proyectos admite la aplicación de un gran número de metodologías docentes entre las que destacan el ABP – Aprendizaje Basado en Proyectos (PBL – Project Based Learning) y el AC – Aprendizaje Cooperativo (CL – Cooperative Learning), entre otras. Por otro lado, las asignaturas de Proyectos a menudo suelen emplearse como un espacio idóneo para la evaluación, más allá de las competencias específicas asociadas al proyectar, de algunas de las competencias transversales o genéricas, entre las que destacarían las siguientes: trabajo en grupo, comunicación eficaz oral y escrita o búsqueda eficiente de información. Esta comunicación versará sobre la potenciación de la competencia genérica “Tercera Lengua” en titulaciones técnicas en base a la experiencia de impartición de la asignatura “Proyectos” en la titulación de Ingeniería Aeronáutica de la ETSEIAT (Escola Tècnica Superior d’Enginyeries Industrial i Aeronàutica de Terrassa).Postprint (published version

A white paper on future NJIT research for the new president of NJIT from the NJIT Faculty Senate Research Committee

The NJIT Faculty Senate Committee on Research, Scholarship, and Creative Academic Activities (Research Committee) drafted a white paper on recommendations for Future NJIT Research that represents the consensus of the Research Committee. It was approved unanimously by the Faculty Senate and sent to the new president of NJIT. There are three main sections 1) Faculty Governance - where we recommend a) decentralizing both authority and responsibility in support of increased innovation and productivity based on Transparency, Communication, and Equity and b) eliminating the disconnect between the Institute’s vision and mission and the P&T process to strengthen interdisciplinary and cross-disciplinary research; 2) Graduate Students & Postdocs – where we recommend increasing the number of PhD students and postdoc researchers, and; 3) Resources – where we recommend enhancing and efficiently utilizing resources for research, including efficient allocation of space, TA lines, support staff, equipment, etc