Advances in computational morphodynamics using the International River Interface Cooperative (iRIC) software

Abstract

Results from computational morphodynamics modeling of coupled flow-bed-sediment systems are described for 10 applications as a review of recent advances in the field. Each of these applications is drawn from solvers included in the publicdomain International River Interface Cooperative (iRIC) software package. For mesoscale river features such as bars, predictions of alternate and higher mode river bars are shown for flows with equilibrium sediment supply and for a single case of oversupplied sediment. For microscale bed features such as bedforms, computational results are shown for the development and evolution of two-dimensional bedforms using a simple closure-based two-dimensional model, for two-and three-dimensional ripples and dunes using a three-dimensional large-eddy simulation flow model coupled to a physics-based particle transport model, and for the development of bed streaks using a three-dimensional unsteady Reynolds-averaged Navier-Stokes solver with a simple sedimenttransport treatment. Finally, macroscale or channel evolution treatments are used to examine the temporal development of meandering channels, a failure model for cantilevered banks, the effect of bank vegetation on channel width, the development of channel networks in tidal systems, and the evolution of bedrock channels. In all examples, computational morphodynamics results from iRIC solvers compare well to observations of natural bed morphology. For each of the three scales investigated here, brief suggestions for future work and potential research directions are offered.

Numerical simulation of large wood deposition patterns and responses of bed morphology in a braided river using large wood dynamics model

“…This 2D plane numerical solver is further described in detail on the Nays2DH and iRIC websites (e.g. Shimizu et al ., , ; http://i-ric.org/en). We only describe herein the application of the particle method to wood motion.…”

The Role of Large-Scale Bedforms in Driftwood Storage Mechanism in Rivers

“…Herein, we use a two-dimensional morphodynamic model, Nays2DH [20], which is a plane two-dimensional morphodynamic model incorporated in the international River Interface Coorperative (iRIC) software package [21,22] to reproduce the various types of large-scale bedforms including alternate bars and multiple bars (braided channel). This is an unsteady shallow water flow model with a Manning-Strickler type roughness model for the flow field, and an equilibrium-bedload transport model for sediment transport and morphodynamics.…”

Three‐dimensional antidunes coexisting with alternate bars

“…For instance, 3D bedforms cause secondary flow circulations (Maddux et al, 2003a,b), and the level of turbulence increases or decreases depending on the shape of the crests of 3D dunes (Venditti, 2007). Based on these experimental studies, the motion of 3D dunes has been computationally modelled by coupling large eddy simulation (LES) and the sediment continuity equation (Nabi et al, 2013;Khosronejad et al, 2015;Shimizu et al, 2019).…”