Large structure simulation for landscape evolution models
Year: 2024
Type: article
Abstract: . Because of the chaotic behavior of the coupling between water flow and sediment erosion and transport, without any special treatment the practical results of landscape evolution models (LEM) are likely to be dominated by numerical errors. This paper describes two areas of improvement that we believe are necessary for the successful simulation of landscape evolution models. The first one concerns the expression of the water flux that was initially rebuilt in a recent paper in a mathematically consistent way for the cell-to-cell multiple flow direction algorithms, thanks to a reinterpretation as a well chosen discretization of the Gauckler-Manning-Strickler continuous equation. Building on those results, we introduce here a general framework allowing to derive consistent expressions of the water flux for the most commonly used multiple/single flow direction (MFD/SFD) water flow routines, including node-to-node versions. If having a consistent water flux is crucial to avoid any mesh size dependence in a LEM and controlling the consistency error, the expected non-linear self amplification mechanisms of the water and sediment coupling can still lead to simulations blurred by numerical errors. Those numerical instabilities being highly reminiscent of turbulence induced instabilities in computational fluid dynamics (CFD), in the second part of our paper we present a ``large structure simulation'' (LSS) approach for LEM, mimicking the large-eddy simulations (LES) used for turbulent CFD. The LSS allows to control numerical errors while preserving the major physical based geomorphic patterns.
Source: Earth Surface Dynamics
Authors: Julien Coatléven, Benoit Chauveau
Institution: IFP Énergies nouvelles
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,682
OpenAlex ID: W4402521782