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A new one-dimensional numerical model for unsteady hydraulics of sediments in rivers

Eman AlQasimi and Tew-Fik Mahdi

Article (2020)

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Cite this document: AlQasimi, E. & Mahdi, T.-F. (2020). A new one-dimensional numerical model for unsteady hydraulics of sediments in rivers. SN Applied Sciences, 2(9), p. 1480. doi:10.1007/s42452-020-03284-y
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This paper presents the model UMHYSER-1D (Unsteady Model for the HYdraulics of SEdiments in Rivers 1-D), a one-dimensional hydromorphodynamic model capable of representing water surface profiles in a single river or a multiriver network, with different flow regimes considering cohesive or non-cohesive sediment transport. It has both steady and unsteady flow and sediment modules. For steady gradually varied flows, UMHYSER-1D uses the standard step method to solve the energy equation and the “NewC” scheme for the de St Venant equations. For sediment transport, UMHYSER-1D uses two methods: for long-term simulation, the unsteady terms of the sediment transport continuity equation are ignored, and a non-equilibrium sediment transport method is used. For short-term simulation, the convection–diffusion equation, with a source term arising from sediment erosion/deposition is solved using the fractional step method. The equation without the source term is solved with an implicit finite-volume method, then the equation with source term is solved. Internal boundary conditions, such as time-stage tables, rating curves, weirs, bridges, and gates are simulated. Incorporated is the active layer concept, which allows selective erosion, enabling the simulation of bed armoring. Non-cohesive sediment transport equations and cohesive sediment physical processes are applied to calculate the sediment deposition and erosion. Finally, UMHYSER-1D empirically accounts for bed geometry adjustments by using a relationship between erosion width and flow rate, an angle of repose condition for bank stability and three minimization theories. The presented validation and application cases show UMHYSER-1D’s capabilities and predicts its promising role in solving complex, real engineering cases.

Uncontrolled Keywords

One-dimensional model; UMHYSER-1D; Fractional step method implicit finite-volume method; Unsteady sediment transport; Bed geometry adjustment; Minimization theories

Open Access document in PolyPublie
Subjects: 1000 Génie civil > 1005 Génie hydraulique
2950 Mathématiques appliquées > 2960 Modélisation mathématique
4000 Sciences de la terre > 4007 Sédimentologie
Department: Département des génies civil, géologique et des mines
Research Center: Non applicable
Grant number: RGPIN-2016-06413
Date Deposited: 06 Nov 2020 12:38
Last Modified: 07 Nov 2020 01:20
PolyPublie URL: https://publications.polymtl.ca/5479/
Document issued by the official publisher
Journal Title: SN Applied Sciences (vol. 2, no. 9)
Publisher: Springer
Official URL: https://doi.org/10.1007/s42452-020-03284-y


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