DLBreach 1D/2D/3D
DLBreach1D/2D/3D is a series of one-, two- and three-dimensional physically-based Dam/Levee Breach models developed by Wu and his group (Wu and Wang 2007, 2008; Wu et al. 2012; Marsooli and Wu 2014a, 2014b). These models can simulate the dam/levee breaching processes and the induced flood propagation.
The 1D model is capable of simulating the dam-break flows over movable bed and the sediment transport and morphology changes in the dam/levee breaching processes. The hydrodynamic model adopts the generalized shallow water equations, which consider the effects of sediment transport and bed change on the flow. The sediment model computes the non-equilibrium transport of total load (either bed-material load or separated as bed load and suspended load). The effects of sediment concentration on sediment settling and entrainment are considered in determining the sediment settling velocity and transport capacity. The governing equations are solved by an explicit finite-volume method with the first-order upwind scheme for intercell fluxes (Wu and Wang 2007, 2008).
DLBreach2D is a depth-averaged two-dimensional model simulating the unsteady flow and non-cohesive sediment transport due to embankment break and overtopping breaching. The model adopts the generalized shallow water equations that consider the effects of sediment transport and bed change on the flow, thus leading to coupled calculations of these processes. It computes the non-equilibrium total-load sediment transport and considers the non-cohesive embankment slope avalanching. The model solves the governing equations using an explicit finite volume method on a rectangular grid, with the HLL approximate Riemann solver to handle the mixed-regime flows generated by embankment break/breaching and the MUSCL piecewise reconstruction method to reach second-order accuracy in space. It uses a varying time step length that satisfies both the CFL condition and the limitation that the bed change is less than about ten percent of the local flow depth at each time step (Wu et al. 2012).
The 3D model is capable of simulating dam-break flows with sediment transport over movable beds. The hydrodynamic model solves the 3-D Reynolds-Averaged Navier-Stokes (RANS) equations using a finite-volume method on collocated hexahedral meshes. The Volume-of-Fluid (VOF) technique with the Compressive Interface Capturing Scheme for Arbitrary Meshes (CICSAM) is used to track the water surface boundary. The sediment transport model solves the non-equilibrium transport equations of suspended load and bed load separately and in turn calculates the resulting bed change. A moving mesh technique is adopted to track the time evolution of bed topography. The grid moving velocity and computational cell volume change due to the moving mesh are taken into consideration when the hydrodynamic and sediment transport equations are discretized. Compared with 1D and 2D models, the 3D model improves the accuracy of calculated morphological changes at the initial stages of dam-break flow, near the wave front, and around in-stream structures (Marsooli and Wu 2014a, 2014b).
References:
W. Wu and S. S.Y. Wang (2007). “One-dimensional modeling of dam-break flow over movable beds,” J. Hydraulic Eng., ASCE, 133(1), 48–58.
W. Wu and S. S.Y. Wang (2008). “One-dimensional explicit finite-volume model for sediment transport with transient flows over movable beds,” J. Hydraulic Research, IAHR, 46(1), 87–98.
W. Wu, R. Marsooli and Z. He (2012). “A depth-averaged two-dimensional model of unsteady flow and sediment transport due to non-cohesive embankment break/breaching.” Journal of Hydraulic Engineering, ASCE, 138(6), 503–516.
R. Marsooli and W. Wu (2014a). “3-D finite-volume model of dam-break flow over uneven beds based on VOF method.” Advances in Water Resources, 70, 104–117, http://dx.doi.org/10.1016/j.advwatres.2014.04.020 0309-1708.
R. Marsooli and W. Wu (2014b). “3-D finite-volume model of dam-break flow over movable beds.” ASCE, 141(1), 04014066, 1–12, DOI: 10.1061/(ASCE)HY.1943-7900.0000947.