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Caracterização do coeficiente de rugosidade e seu efeito no escoamento em canais naturais: simulação e modelação (à escala) no laboratório de hidráulica: aplicação às ribeiras do Funchal
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Abstract(s)
Esta dissertação tem como objetivos principais: a caracterização e evolução de instrumentos numéricos de demonstração do comportamento do escoamento, nomeadamente, a caracterização do coeficiente de rugosidade em canais naturais; utilização de um modelo à escala reduzida para simulação hidrodinâmica, considerando diferentes coeficientes de rugosidade; comparação dos diferentes resultados obtidos entre os coeficientes adotados e estimados; análise e controle em canais naturais, situação, que pode ser nefasta para o dimensionamento de obras hidráulicas.
Para uma primeira abordagem é preciso uma recolha de informação bibliográfica disponível, após este processo e recorrendo aos modelos digitais e ao programa ArcGis, são caracterizadas as três bacias hidrográficas da cidade do Funchal, que nos foi possível alcançar os dados das características geométricas, de relevo e drenagem. Após este processo é feita uma análise da precipitação usando folhas de cálculo e dados facultados pelas instituições competentes, de modo a adquirir valores de precipitação média diária e anual para utilização de fórmulas, de modo a fazer o cálculo dos valores para o tempo de concentração e caudais.
De seguida são selecionados os vários troços dos canais em estudo com características morfológicas diferentes relevantes e recorrendo aos equipamentos disponíveis no Laboratório de Hidráulica, modelo reduzido, à folha de cálculo e ao programa HEC-RAS, modelo numérico, executa-se a simulação e estudo desses troços, com a obtenção de resultados semelhantes entre as várias metodologias executadas e de concordância com o expectável para os valores dos diferentes coeficientes de rugosidade considerados.
No final, são apresentadas as conclusões, considerações finais e objetivos a manter ou a alcançar nos imediatos anos, onde incluem, recomendações visando, melhorar o método de caracterização para escoamento em canais naturais, de acordo com os valores dos diferentes coeficientes de rugosidade considerados.
This dissertation has as main objectives: the characterization and evolution of numerical instruments of demonstration of the behavior of outflows, namely the characterization of the roughness coefficient in natural channels; utilization of a reduced model to simulate hydrodynamics, considering different roughness coefficient, comparison of different results obtained between adopted and estimated coefficients; analysis and control in natural channels, situation that could be disastrous for sizing hydrodynamics works. For a first approach, its necessary to select the available bibliography information, after this process and using digital models and ArcGIs program, the three watersheds of the city of Funchal that were possible to reach their geometrical characterization, of relief and drainage, were characterized. After this process an analysis is made of the precipitation using spreadsheets and data provided by competent institutions, in order to acquire daily and annual average values of precipitation for utilization of formulas, in order to calculate values for concentration times and flow rates. Next, various sections of channels are selected in a study with the different relevant morphological characteristics and using equipment available in the Hydraulics Laboratory, reduced model to the spreadsheet and the HEC-RAS program, numeric model, a simulation and study of these channels is executed, obtaining similar results between the various methodologies executed and the concordance with the expectable for the values of the roughness coefficient considered. At last, the final conclusions and considerations are presented as well as the objectives to maintain or to achieve in the immediate years to come, where included are: recommendations aiming, to better the method of characterization for flows in natural channels, according with the different values of roughness coefficient considered.
This dissertation has as main objectives: the characterization and evolution of numerical instruments of demonstration of the behavior of outflows, namely the characterization of the roughness coefficient in natural channels; utilization of a reduced model to simulate hydrodynamics, considering different roughness coefficient, comparison of different results obtained between adopted and estimated coefficients; analysis and control in natural channels, situation that could be disastrous for sizing hydrodynamics works. For a first approach, its necessary to select the available bibliography information, after this process and using digital models and ArcGIs program, the three watersheds of the city of Funchal that were possible to reach their geometrical characterization, of relief and drainage, were characterized. After this process an analysis is made of the precipitation using spreadsheets and data provided by competent institutions, in order to acquire daily and annual average values of precipitation for utilization of formulas, in order to calculate values for concentration times and flow rates. Next, various sections of channels are selected in a study with the different relevant morphological characteristics and using equipment available in the Hydraulics Laboratory, reduced model to the spreadsheet and the HEC-RAS program, numeric model, a simulation and study of these channels is executed, obtaining similar results between the various methodologies executed and the concordance with the expectable for the values of the roughness coefficient considered. At last, the final conclusions and considerations are presented as well as the objectives to maintain or to achieve in the immediate years to come, where included are: recommendations aiming, to better the method of characterization for flows in natural channels, according with the different values of roughness coefficient considered.
Description
Keywords
Canal natural Coeficiente de rugosidade Hidrodinámica de escoamento Resistência ao escoamento Funchal, Madeira (Portugal) Flow resistance Hydrodynamics flow Natural channels Roughness coefficient Engenharia Civil . Faculdade de Ciências Exatas e da Engenharia