Computation modelling 1d+2d for gradually varied flood flow

Abstract

The proposed model was established to simulate the propagation of gradually varied flood flow in deltas. The model incorporates two flow models: a one-dimensional flow model for the river network and a two-dimensional flow model for the flood plain. The combination of the two models was carried out through the exchange of flow between the river and the adjacent flood plain subareas. The momentum equation of two-dimensional flow model was approximated by a diffusion model; in which only two terms representing the water surface slope and the friction slope are considered. The implicit Preissmann scheme was utilized to discretize the governing equations in an alternate grid. The flood plain subareas whether inundated or not will be treated after each time step.