Enhanced one-way coupled swe-de model for floating body transport

Abstract

Modelling the transport of floating bodies during floods is a topic that must be considered when dealing with flood risk, but many open issues still exist regarding its implementation. The paper presents an enhanced one-way coupled SWE-DE (Shallow Water Equations-Discrete Element) model, focusing on to the algorithm for the rigid body localization and on the interpolation of the flow velocity distribution along the body. The proposed algorithm leads to a smoother variation of the hydrodynamic coefficients. Moreover, the higher accuracy in assigning the flow velocity, needed to compute the forces on the bodies, reduces the dependence on the relative size of the cells and objects. A laboratory case has been used to validate the model in which some rectangular obstacles are present. Obstacles were represented by modelling them as solid walls or by increasing the Manning roughness coefficient. The influence of the two schematizations on the flow field and on the transport of a floating cylinder is evaluated. On overall, varying the obstacle roughness coefficient yield trajectories closer to the observed ones, although external factors, such as the effect of cylinder orientation and of collisions with side walls, may occasionally alter the outcome of the simulation.