Author(s): Akihiko Nakayama; Xin Yan Lye

Linked Author(s): Akihiko Nakayama

Keywords: Rainfall-runoff process; Overland flow; Urban terrain; Smoothed particle hydrodynamics

Abstract: The three-dimensional (3-D) Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) has been reformulated to simulate overland flow on natural terrain due to rainfalls. The rainfall is lumped into discrete particles falling over the terrain and the overland flow is simulated as three-dimensional free surface flows over topography following the WCSPH framework. The terrain and objects on it such as buildings and other structures are represented by boundary particles that are distributed over the combined surfaces having the normal directions and the roughness height used for setting the dynamic boundary conditions and the actual and the potential moisture contents used to set the infiltration conditions. The basic method is verified with experimental results of rainfall runoff from laboratory model plots. It is found that with the realistic wall friction model represented by roughness height the patchy thin overland flow on urban terrain can be simulated more realistically than existing two-dimensional methods based on shallow-water equations.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P2137-cd

Year: 2025