Morphological reactions of schematic alluvial rivers:Long simulations with a 0-D model  

作　　者：M.Franzoia M.Nones 

机构地区：[1]Department of Civil,Environmental and Architectural Engineering,University of Padova [2]Interdepartmental Centre for Industrial Research in Building and Construction-Fluid Dynamics Unit, University of Bologna

出　　处：《International Journal of Sediment Research》2017年第3期295-304,共10页国际泥沙研究（英文版）

摘　　要：The paper presents a 0-D model of an alluvial watercourse schematized in two connected reaches,evolving at the long time-scale and under the hypothesis of Local Uniform Flow. Each reach is defined by its geometry(constant length and width, time-changing slope) and grain-size composition of the bed,while the sediment transport is computed using a sediment rating curve. The slope evolution is provided by a 0-D mass balance and the evolution of the bed composition is computed by a 0-D Hirano equation. A system of differential equations, solved with a predictor-corrector scheme, is derived and applied to the schematic watercourse to simulate the morphological response to changing initial conditions, and the evolution towards long-term equilibrium conditions. Differently from a single-reach 0-D schematization with uniform grain-size, besides the simplifications adopted, the model proposed here simulates the behaviour of alluvial rivers in a physically-based way, showing a grain-size fining in the downstream direction accompanied by milder slopes, and a tendency to develop concave longitudinal profiles.The paper presents a 0-D model of an alluvial watercourse schematized in two connected reaches,evolving at the long time-scale and under the hypothesis of Local Uniform Flow. Each reach is defined by its geometry(constant length and width, time-changing slope) and grain-size composition of the bed,while the sediment transport is computed using a sediment rating curve. The slope evolution is provided by a 0-D mass balance and the evolution of the bed composition is computed by a 0-D Hirano equation. A system of differential equations, solved with a predictor-corrector scheme, is derived and applied to the schematic watercourse to simulate the morphological response to changing initial conditions, and the evolution towards long-term equilibrium conditions. Differently from a single-reach 0-D schematization with uniform grain-size, besides the simplifications adopted, the model proposed here simulates the behaviour of alluvial rivers in a physically-based way, showing a grain-size fining in the downstream direction accompanied by milder slopes, and a tendency to develop concave longitudinal profiles.

关 键 词：Alluvial rivers Local Uniform Flow Morphological equilibrium Physically-based 0-D model River morphology Sediment transport 

分 类 号：TV147[水利工程—水力学及河流动力学]