Automated detection of instability-inducing channel geometry transitions in saint-venant simulation of large-scale river networks
Journal
Water (Switzerland)
Journal Volume
13
Journal Issue
16
Date Issued
2021
Author(s)
Abstract
A new sweep-search algorithm (SSA) is developed and tested to identify the channel geometry transitions responsible for numerical convergence failure in a Saint-Venant equation (SVE) simulation of a large-scale open-channel network. Numerical instabilities are known to occur at “sharp” transitions in discrete geometry, but the identification of problem locations has been a matter of modeler’s art and a roadblock to implementing large-scale SVE simulations. The new method implements techniques from graph theory applied to a steady-state 1D shallow-water equation solver to recursively examine the numerical stability of each flowpath through the channel network. The SSA is validated with a short river reach and tested by the simulation of ten complete river systems of the Texas–Gulf Coast region by using the extreme hydrological conditions recorded during hurricane Harvey. The SSA successfully identified the problematic channel sections in all tested river systems. Subsequent modification of the problem sections allowed stable solution by an unsteady SVE numerical solver. The new SSA approach permits automated and consistent identification of problem channel geometry in large open-channel network data sets, which is necessary to effectively apply the fully dynamic Saint-Venant equations to large-scale river networks or for city-wide stormwater networks. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Subjects
Hydrodynamics; Large-scale river modeling; Numerical instability; River network simulation; Saint-Venant equations
SDGs
Other Subjects
Equations of motion; Geometry; Graph theory; Numerical methods; 1D shallow water equations; Automated detection; Discrete geometry; Hydrological condition; Numerical convergence; Numerical instability; Numerical solvers; Saint Venant equation; Rivers; convergence; geometry; hurricane event; river engineering; shallow-water equation; simulation; stormwater; Gulf; Gulf Coast; Papua New Guinea; Texas; United States; Trachinotus falcatus
Type
journal article