A Non-Equilibrium Sediment Transport Model for Dam Break Flow over Moveable Bed Based on Non-Uniform Rectangular Mesh

Abstract

The use of multiple-level non-uniform rectangular mesh in coupled flow and sediment transport modeling is preferred to achieve high accuracy in important region without increasing computational cost greatly. Here, a robust coupled hydrodynamic and non-equilibrium sediment transport model is developed on non-uniform rectangular mesh to simulate dam break flow over movable beds. The enhanced shallow water and sediment transport equations are adopted to consider the mass and momentum exchange between the flow phase and sediment phase. The flux at the interface is calculated by the positivity preserving central upwind scheme, which belongs to Godunov-type Riemann-problem-solver-free central schemes and is less expensive than other popular Riemann solvers while still capable of tracking wet/dry fronts accurately. The nonnegative water depth reconstruction method is used to achieve second-order accuracy in space. The model was first verified against two laboratory experiments of dam break flow over irregular fixed bed. Then the quantitative performance of the model was further investigated by comparing the computational results with measurement data of dam break flow over movable bed. The good agreements between the measurements and the numerical simulations are found for the flow depth, velocity and bed changes.

Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

“…The same scenario analyzed here of a dam-break caused by a partial failure of the dam over a fixed bed has been simulated with different numerical methods by several authors (e.g., [35][36][37][38]). These authors have also considered movable bed conditions [39,40]. However, and differently from the present work, all of them considered a dry bed downstream of the gate and an open boundary at the end of the channel, thus ignoring wave reflections at the end wall.…”

The morphology and stratification of giant eddy bars reflect the variation in shape of palaeoflood hydrographs: A flume study

“…Further advances require not only careful fieldwork and complex numerical modelling but also controlled experimentation using scaled laboratory hydraulic models. Hydraulic modelling within flumes, of exceptional palaeoflood behaviour and the associated landform development, has been neglected but can shed light on process controls (Carrivick, 2010; Carrivick et al, 2011; Goutiere et al, 2011; Greco et al, 2012; Wu et al, 2018). Herein, scaled hydraulic models are used to explore how the variation in flood hydrograph shapes influence sediment deposition processes and giant bar morphology.…”

Coupled and splitting bedload sediment transport models based on a modified flux-wave approach

“…Generally, capacity or equilibrium models such as the Exner equation are considered in the capacity regimes, and mainly evaluated based upon local hydrodynamic conditions (Cao et al, 2011(Cao et al, , 2012(Cao et al, , 2016. Non-capacity or non-equilibrium models are obtained through mass exchange with the bed, comprise spatial and temporal lag effects between transport capacity and flow conditions (Cao et al, 2016) and can provide more accurate results for strong interaction taking place between the free-surface and bedload sediment flow (Wu et al, 2004(Wu et al, , 2018.…”