Modelling sediment transport using a lightweight bed material

Abstract

Details are given of a combined physical and numerical model study of sediment transport processes in a square harbour caused by tidal motion. The effects on bed level changes due to tidal currents and the configuration of the harbour entrance were investigated. A lightweight material called Cation Resin was used in this study to represent bed sediments in the laboratory experiments. This material enabled the erosion and deposition processes to be exaggerated within the model harbour, in which the magnitude of the flow velocities was relatively small. An unstructured mesh generation technique, namely a quad-tree grid, was incorporated into an existing two-dimensional depth-integrated numerical model to predict the transport of water quality constituents and sediment particle fluxes. The numerical model was further refined to include the prediction of bed level changes. Detailed comparisons between the numerical model predictions and the laboratory data were undertaken. It was found that the numerical model predictions and the laboratory measurements were in good agreement. It was also concluded that Cation Resin was an appropriate material to use for physical modelling of sediment transport processes in laboratory model studies.

Sediment scaling for Mud Mountain fish barrier structure

“…Correctly selecting the appropriate physical model sediment is critical for properly simulating the prototype behavior of the proposed structure (Franco 1978). Numerous studies (Carr et al 2015;Einstein and Chien 1956;Henriquex et al 2008;Kocyigit et al 2005;Lu et al 2013;Yalin 1989) have expended extensive effort in an attempt to replicate prototype sediment behavior in movable bed models. Properly capturing the movable bed freedom is imperative when channel modifications or complex flow patterns alter bed alignment.…”

3D Layer-Integrated Modelling of Morphodynamic Processes Near River Regulated Structures

“…Olsen (1999) applied a 2-D depth-averaged numerical model to calculate bed level changes in a reservoir which was flushed by flood flows. Kocyigit et al (2005) presented the refinement of a 2-D depth-integrated numerical model for predicting the long-term bed level changes in an idealised model harbour. They reported an under-prediction of the depth of erosion, which was thought to be due to the model not correctly predicting the lateral movement of sediment.…”