Modelacao matematica de uma rede de rega com comando por montante

Herein is presented a mathematical model (model SIMCAR) developed to solve the gradually varied unsteady flow in an upstream controlled canal system, resulting from the fluctuations in the inflow rate and/or fluctuations in the lateral outflows at the canal off takes. Model SIMCAR simulates the unsteady flow phenomena in branched canal networks equipped with automatic radial gates (upstream constant water level, AMIL type) and also regarding other hydraulic structures: transitions and siphons. The model is based on the Saint-Venant system of equations, which are solved by a finite-difference technique with a four-point implicit scheme weighted in time and space (Pressman scheme). The final linear system of equations is solved by the double-sweep algorithm. Model calibration and validation are made for two experimental case studies presented herein. A few model applications are also proposed. In this work another model is also presented: the model EFICAR and some numerical results, corresponding to two years of experiments in the irrigation system studied. This model determines the conveyance, distribution and system efficienciesAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga