Dam-break hazard assessment with geomorphic flow computation, using WOLF 2D hydrodynamic software

摘要

WOLF 2D software solves the 2D shallow-water equations on any evolutive grid, dealing with natural topography and mobile bed. WOLF 2D is part of WOLF free surface flows computation package, which has been completely developed at the University of Liege. A mass balance for bed load sediments is coupled to the hydrodynamic model. Solid discharges are estimated by means of reliable transport laws. Side slope stability analysis are systematically performed to take gravity induced solid discharges into account. The same finite volume technique in each computer code solves the equations, formulated in a conservative form to ensure exact mass and momentum balance, even across moving hydraulic jumps. An original splitting of the convective terms has been specifically developed for the model, in order to handle properly transient discontinuities. Its efficiency is highlighted through comparisons with analytical solutions. WOLF 2D has been successfully applied to the simulation of the flooding triggered by an instantaneous and total failure of a large dam in Belgium (Eupen). This case study demonstrates the applicability of the solver to extreme erosive flows on any realistic mobile topography. By revealing severe visible geomorphic processes, the simulation also confirms the relevance of handling morphology changes in dam-break hazard assessment. Functional risk maps have been plotted to exhibit crucial practical information, like maximal water heights, in an incredibly convenient way to interpret. Such data reveals a major interest in the scope of prevention policies or protection plans for populations and goods.