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EE - Trabalhos apresentados em eventos

URI permanente para esta coleçãohttps://rihomolog.furg.br/handle/1/515

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1996 - 19993

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Data inicial: 1996Data final: 1999

Resultados da Pesquisa

Agora exibindo 1 - 3 de 3
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    Three dimensional simulation of high compressible flows using a subcycling algorithm for time integration
    (1999) Teixeira, Paulo Roberto de Freitas; Awruch, Armando Miguel
    An algorithm to simulate 3-D high compressible flows using the finite element method and a multi-time-step integration technique with subcycles is presented in this work. An explicit two-step Taylor-Galerkin scheme is adopted to integrate in time continuum equations. When explicit schemes are used, the time steps must satisfy some stability conditions. If the smallest critical time-step is adopted uniformely for the whole domain, the integration scheme may consume a large amount of CPU time. Multi-time-step integration techniques are very suitable in these cases because elements and nodes are separated into several groups and a different time-step is assigned to each group. In this way, each group of elements is integrated with a time interval wich is much closer to the critical time steps of the elements in the group. This results in great computational savings, mainly when elements size and properties are very different, leading to significative differences of the local critical time steps values. Multi-time-steps integration techniques are also very useful in transient problems, taking into account that at the end of each subcycle, values of the unknowns at the same time level are obtained. The multi-time-step algorithm is applied to analyze the supersonic flow (Mach=8,5) past a sphere immersed in a non viscous flow, and results and computational performance are compared with those obtained when a uniformly time-step is used over the whole domain.
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    Análise estatística e espectral de dados meteorológicos de superfície
    (1996) Pinto, Ernesto Luiz Casares; Krusche, Nisia; Piccoli, Humberto Camargo
    This article discusses the spectral analysis of daily meteorological data, extracted from the Meteorological Center of the University of Rio Grande (FURG). The time series corresponds to temperature, atmospheric pressure, humidity and evaporation, measured at Rio Grande city, from January 1990 to August 1995. The spectral approach was made using the professional version of MATLAB Software, mainly the Signal Processing Toolbox. Initially, tests were made for stationarity, periodicity and normality of the time series. Afterwards, the spectral and cross-spectral estimation was computed as well as the autocorrelation, cross-correlation and coherence spectrum of the data analysed. During processing of the time series the Hanning Window, and the low-pass and high-pass Butterworth filters were used. Despite the low frequency data aquisition (one value per day), the spectral analysis shows satisfactory results.
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    Metodologias de desenvolvimento de produtos: conhecimento e uso
    (1998) Brasil, Antônio Domingues; Fiod Neto, Miguel
    This is a study about knowledge and the use of methods for development of products,based on interviews with professionals from thirty medium and large firms within the states of Santa Catarina and Rio Grande do Sul,Brazil. The study reveals that the basic theoretical knowledge of the professionals is at the same level and almost always as poor as their knowledge of methodological aspects for the development of products. The procedures that guide their activities are predominantly informal an without any link with the models proposed by researchers.