Development of a Three-Dimensional Unstructured Mesh Finite-Element Model for Flood Propagation

In this paper, a three-dimensional (3D) finite-element model for flooding has been developed, which can be applied to different types of flooding. The theoretical methodology has been introduced in details. The new model has been tested with an idealized case and the Thacker test case, then validated by a tsunami-caused coastal flooding experiment. The advantages of the new flooding model developed in this paper over existing ones are (1)the use of unstructured meshes that makes it possible to obtain more detailed information about local flow structures close to isolated objects and long linear objects; (2)the 3D modeling ability that provides increased accuracy where vertical inertia is important; (3)the use of a wetting and drying (WD) method that allows the free-surface height to be treated with a high level of implicitness and stability, allowing relatively large time steps to be used; and (4)control of the conditioning of the resulting matrix equations in high-aspect ratio domains.