Análise dinâmica não linear da interação solo-estrutura em plataformas marítimas

This work deals with the dynamic nonlinear analysis of soil-structure interaction in offshore platforms, during its installation and operation. Hence, it was developed a numerical model to allow the representation of the soil fundamental plastic and rheological properties. This model also enhances the utilization of complete constitutive relations for soil. Several applications in structural dynamics and wave propagation problems were studied. They were solved by an implicit incremental-iterative formulation for the nonlinear movement equations. Finally, some conclusions regarding the performance of the developed numerical procedures are presented, and some considerations on further developments in this field are mentioned.O presente trabalho trata da análise dinâmica não-linear da interação solo-estrutura em plataforma marítima, tanto durante sua instalação quanto em condições de operação. Desta forma desenvolveu-se um modelo numérico para a representação das propriedades plásticas e reológicas fundamentais do solo, e que possibilita ainda, o emprego de relações constitutivas completas. Estudam-se, portanto, diversas aplicações a problemas da dinâmica estrutural e propagação de ondas, que foram solucionadas através de uma formulação implícita incremental iterativa das equações não-lineares de movimento. Finalmente, apresentam-se algumas conclusões quanto ao desempenho dos procedimentos desenvolvidos e efetuam-se considerações sobre desenvolvimentos futuros nesta área

Simulating Vortex Shedding at High Reynolds Numbers.

The turbulent vortex shedding arising from the cross flow past a circular cylinder is analyzed using a Large Eddy Simulation (LES) procedure. In particular, no explicit sub-grid stress model is employed. Rather, the unresolved scales are dealt implicitly by a stabilized Petrov-Galerkin finite element formulation used in conjunction with a time-space adaptive scheme. The numerical results are compared with available experimental data on force coefficients and vortex shedding frequency.O desprendimento de vórtices de turbulência resultante do fluxo transversal passado de um cilindro circular é analisado usando um procedimento Grande Eddy Simulação (LES). Em particular, nenhum modelo de estresse sub-grade explícita é empregado. Em vez disso, as escalas não resolvidos são tratados implicitamente por uma Petrov-Galerkin formulação estabilizada de elementos finitos utilizado em conjunto com um esquema adaptativo de tempo-espaço. Os resultados numéricos são comparados com dados experimentais disponíveis sobre os coeficientes de força e frequência vortex derramamento

Data reduction in scientific workflows using provenance monitoring and user steering

International audienceScientific workflows need to be iteratively, and often interactively, executed for large input datasets. Reducing data from input datasets is a powerful way to reduce overall execution time in such workflows. When this is accomplished online (i.e., without requiring the user to stop execution to reduce the data, and then resume), it can save much time. However, determining which subsets of the input data should be removed becomes a major problem. A related problem is to guarantee that the workflow system will maintain execution and data consistent with the reduction. Keeping track of how users interact with the workflow is essential for data provenance purposes. In this paper, we adopt the " human-in-the-loop " approach, which enables users to steer the running workflow and reduce subsets from datasets online. We propose an adaptive workflow monitoring approach that combines provenance data monitoring and computational steering to support users in analyzing the evolution of key parameters and determining the subset of data to remove. We extend a provenance data model to keep track of users' interactions when they reduce data at runtime. In our experimental validation, we develop a test case from the oil and gas domain, using a 936-cores cluster. The results on this test case show that the approach yields reductions of 32% of execution time and 14% of the data processed