Numerical Modelling of Bed Evolution in Braided Channel Systems

by Forrest M. Holly, Jr., Univ of Iowa, Dep of Civil &, Environmental Engineering, Iowa, City, IA, USA,
J. C. Yang, Univ of Iowa, Dep of Civil &, Environmental Engineering, Iowa, City, IA, USA,



Document Type: Proceeding Paper

Part of: Hydraulics and Hydrology in the Small Computer Age

Abstract: The overall modelling approach adopted is based on an assumption of quasi-steady flow. The numerical algorithm is based on a split-operator approach, in which the flow energy equation, sediment continuity equation, bed armoring, and bed material sorting processes are computed separately but iteratively within a computational time step. Linearization of the energy equation and subsequent substitution into the water continuity constraint at model junctions leads to a system of linear equations for the water-level changes at each node. Once this system is solved, the water levels, discharges, and sediment-transport, capacities at individual computational points are readily computed. The paper presents the essential details of the computational methods employed and describes limited application to a northern braided river.

Subject Headings: Steady flow | Fluid flow | Channel flow | Bed materials | Computing in civil engineering | Linear functions | Water level | Sediment transport

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