Many post-tsunami or flash flood field investigations have shown that debris carried by the flows contributed greatly to the damage to structures on the land. However, few simulation models have been developed to predict debris behaviour under supercritical flow conditions involving interactions of debris-fluid, debris- debris, and debris-structure. This study attempts to model three-dimensional (3-D) debris movement combined with a shallow water flow model. This model will use the smoothed particle hydrodynamics (SPH) method to solve the depth-average shallow water equations (SWEs) and represents debris movement using the modified Morison equation. Several discrete points will represent each debris object and its collision mechanism will be solved using the distributed-contact discrete-element-method (DCDEM). The flow model is formulated based on the Euler-Lagrange equation which takes into account the vertical velocity component so that it can be combined with 3-D debris motion. This model will be implemented in open-source software called DualSPhysics with a parallel computing system using OpenMP and a graphics processing unit (GPU). The SWE-SPH and debris flow models will be validated against experimental, analytical, and field survey data. This model is expected to be a tool to predict the hazard caused by extreme floods, such as tsunamis and flash floods

debris, flash flood, tsunami, SPH, GPU, numerical simulation

• Dr. Ir. Juliastuti, M.T.

• Dr. Ir. Oki Setyandito, ST., M.Eng., IPM

• Yureana Wijayanti, S.T., M.Eng., Ph.D.

• Muhammad Hafiz Aslami, S.T., M.Eng., Ph.D