Mestrado em Engenharia Ambiental

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http://repositorio.ufes.br/handle/10/17612

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Navegando Mestrado em Engenharia Ambiental por Autor "Almeida, Murilo Pereira de"

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    Acoplamento de modelagem do escoamento de mesoescala e microescala meteorológica no interior do dossel urbano
    (Universidade Federal do Espírito Santo, 2020-02-19) Maciel, Felipe Simões; Reis Junior, Neyval Costa; https://orcid.org/0000000261594063; http://lattes.cnpq.br/4944106074149720; https://orcid.org/0000-0002-8381-3052; http://lattes.cnpq.br/9239461505806925; Almeida, Murilo Pereira de; https://orcid.org/0000-0002-6230-577X; http://lattes.cnpq.br/1769797384421103; Santos, Jane Meri; https://orcid.org/0000000339332849; http://lattes.cnpq.br/0120226021957540
    The present work investigates the impact of the use of mesoscale meteorological model data coupled as boundary conditions for microscale CFD (Computational Fluid Dynamics) models for a real urban area. Numerical simulations were performed using CFD considering transient input data from the WRF model and from the fixed weather station. The geometry studied is based on a real urban area of Metropolitan Region of Vitória, in Brazil. The microscale CFD modeling consists of solving the mass and momentum conservation equations for transient flow, on a discretized domain formed by 3D hexahedral mesh. The standard k-ε model was used for the treatment of turbulence. The coupling of wind speed and direction data from the mesoscale model (considering the macroscopic dynamics of the atmosphere) is carried out by using a User Defined Function (UDF), which basically reads output data from the WRF simulations and creates boundary conditions for the microscale CFD simulations. The same UDF was used to couple data from Vitória Airport weather station as input data for CFD domain. In order to evaluate the accuracy of the simulations, a 16 days field campaign was also conducted to measure wind speed and direction at three points within the neighborhood. The considerable gain was observed comparing WRF results with CFD-WRF coupling results at the monitoring points. The velocity and direction values from the simulations follow a trend similar to the data measured in the field and are in accordance with commonly used acceptance criteria. For the case with airport station data as an entry condition, there is a significantly greater agreement between the data. This is due to the better quality of input data provided by the airport meteorological station. The result of microscale modeling using mesoscale data is shown to be sensitive to the quality of the input data, since the better agreement between the results is observed in periods of better WRF data quality. Also, good results were obtained from the use of measured data as input for the CFD model. Using data from mesoscale models such as WRF is a viable option for studying wind field modeling and pollutant dispersion in areas where meteorological measurement stations are not available.
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    Influência de partículas não-erodíveis com diferentes granulometrias na emissão em leitos e em pilhas de estocagem
    (Universidade Federal do Espírito Santo, 2018-06-05) Morais, Cristina Lima de; Furieri, Bruno; Caliman, Maria Clara Schuwartz Ferreira; Santos, Jane Meri; Reis Junior, Neyval Costa; Almeida, Murilo Pereira de
    Emission of granular materials stored in stockpiles exposed to wind erosion is an important environmental issue currently discussed. One of the problematic cases are coal and iron ore particles due to the high fugitive emission potential during their handling and storage. Efforts have been made to create and test new models to estimate this type of emission, as in Caliman (2017) case. Caliman (2017) builded and validated the model using experiments with stockpiles composed of a binary mixture of erodible and non-erodible particles in two different proportions of non-erodible particles. As in nature the wind erosion processes occur in a wide range of diameters at various velocities, the present work aimed to investigate the influence of different non-erodible particle size distribution on beds and stockpile emission through the Caliman (2017) model. For the application of the model, some parameters were defined investigate the influence of different non-erodible particle size distribution on beds and stockpile emission through the Caliman (2017) model. In addition, an analysis of the evolution of the surface cover rate of the piles of the experiments used was performed to verify the behavior described in the literature. The results showed that the numerical simulations of the bed did not offer improvements in the modeled emission values. The relationship between the coverage rate and the eroded final height can still be considered linear for mixtures composed of different non-erodible granulometries with variable erodibility. Despite the errors, it is observed that the physical tendency of the erosion phenomenon was well modeled. The model has a physical basis both when it was created and when it was tested in the present work, requiring only deeper investigations of which, among the considerations made, propagated more errors. The analysis of the evolution of the surface cover rate of the experimental piles showed that the particle distribution can be partly explained, both qualitatively and quantitatively. However, not all phenomena can be visualized and included in the analysis.