dc.contributor.advisor Silva-Araya, Walter F. dc.contributor.author Coaquira-Nina, Julio C. dc.date.accessioned 2019-02-11T19:03:28Z dc.date.available 2019-02-11T19:03:28Z dc.date.issued 2006 dc.identifier.uri https://hdl.handle.net/20.500.11801/1783 dc.description.abstract A mathematical model is presented for studying aggradation and degradation due to base level lowering in open channels. The Saint-Venant equations for unsteady flow and the sediment continuity equations for one-dimensional flow were solved using the second-order-accurate explicit finite difference scheme of MacCormack. This algorithm was proposed by Bhallamudi and Chaudhry, (1991). The sediment transport functions of Yang and Ackers-White were introduced in this algorithm. The application of both functions is only for non-cohesive sediments. The initial condition was assumed as steady state for water and sediment flow. The equilibrium state was interrupted by increasing the sediment supply rate for aggradation and base level lowering for degradation. The model was verified with experimental data for aggradation, degradation and filling of a trench. The model produced satisfactory results and could be used to simulate geomorphic changes in alluvial channels as long as the Yang and Ackers-White functions are applicable. In some cases artificial viscosity was added to the algorithm to satisfy stability requirements. en_US dc.description.abstract Un modelo matemático es presentado para estudiar la agradación y degradación debido a un descenso en la elevación del fondo al extremo final aguas abajo en canales aluviales. Las ecuaciones Saint Venant para flujo no-permanente y la ecuación de continuidad de sedimento para flujo unidimensional fueron resueltas usando el esquema de diferencias finitas de MacCormack. Las condiciones iniciales fueron asumidas como flujo uniforme para agua y el flujo de sedimento en equilibrio. La condición de equilibrio fue interrumpida inyectando sedimento en el primer nodo para simular agradación y descendiendo la elevación del fondo al extremo aguas abajo para provocar degradación aguas arriba. El modelo fue verificado con datos experimentales para agradación, degradación, y agradación en una trinchera. El modelo produce resultados satisfactorios y puede ser usado para simular cambios en canales aluviales, siempre que las funciones de Yang y Ackers-White puedan ser aplicados a los datos. En algunos casos se usó viscosidad artificial en el modelo para mantener la estabilidad. en_US dc.language.iso es en_US dc.subject Transporte de sedimentos en_US dc.subject.lcsh Open-channel flow--Mathematical models en_US dc.title Modelo de transporte de sedimento para flujo no permanente con las funciones de Yang y Ackers-White en_US dc.type Thesis en_US dc.rights.license All rights reserved en_US dc.rights.holder (c) 2006 Julio César Coaquira Nina en_US dc.contributor.committee Rivera Santos, Jorge dc.contributor.committee Padilla, Ingrid dc.contributor.representative Arroyo, José R. thesis.degree.level M.S. en_US thesis.degree.discipline Civil Engineering en_US dc.contributor.college College of Engineering en_US dc.contributor.department Department of Civil Engineering en_US dc.description.graduationYear 2006 en_US
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