Testing a new adaptive grid‐based shallow flow model for different types of flood simulations

Abstract

AbstractThis work aims to test a robust numerical tool for modelling different types of floods, e.g. rapid‐varying dam breaks or slow‐evolving inundations. Based on a novel adaptive grid system, the model solves the 2D shallow water equations using a first‐order accurate Godunov‐type scheme to approximate the flood hydrodynamics. The grid dynamically adapts to local topographic features, moving wet–dry interfaces and other flow features. High‐resolution mesh is only generated to those areas of interests. Therefore, it facilitates the accurate prediction of flood fronts and routs and meanwhile maintains efficient simulation. Results are presented for an analytical case of surge reflecting from a standing wall, a laboratory‐scale rapidly varying dam‐break flow and a prototypical case of slowly evolving flood inundation in the 36 km2 floodplain at Thamesmead. To produce results with a similar resolution, the adaptive grid‐based model is found to be considerably more efficient than its uniform grid‐based counterpart.