Modeling dam-break flows in channels with 90 degree bend using an alternating-direction implicit based curvilinear hydrodynamic solver

This paper presents a combined numerical and experimental investigation of dam break induced free-surface flows in channels with 90 degree bend. These types of flows are best described by the two-dimensional shallow water equations (SWE) representing the conservations of mass and horizontal momentums. In this study, the governing equations are solved numerically by means of an alternating-direction implicit (ADI) finite-difference scheme in a curvilinear coordinate and contravariant velocity system. This model is tested by simulating for various flow conditions including dam-break flows onto dry beds in a converging-diverging channel and a channel with 45 degree bend. Good fits of the present model predictions with published laboratory measurements are achieved. To further the validation of the model, a series of physical model tests for dam-break flows in a channel with 90 degree bend were conducted. The predicted time-varying water depths downstream of the dam face are shown to have a fairly good agreement with recorded data from model tests. The present ADI solver is found to be capable of capturing the formation and movement of steep wave fronts.