[H-DS05] Landslides and related phenomena

[HDS05-P18] A simplified depth-integrated model for the transition between rigid and erodible bed conditions in dry granular dam break flow.

*Yi-Ling Tsai¹, Chi-Yao Hung¹ (1.National Chung Hsing University)

Keywords:dry granular flow , granular dam break experiment, depth-integrated model, basal boundary conditions

Different basal boundary conditions (rigid bed/erodible bed) could alter the debris flow's entrainment rate, changing the travel distance and the size of the flow. In previous studies, simulating the flow transition between rigid and erodible boundaries takes much work. In this study, we propose a simplified, unsteady, non-uniform model to simulate the flow transition between the rigid and erodible beds. The model is based on mass, momentum, and kinetic energy conservation. We apply the linearized mu(I) rheology to describe granular deformation and assume Coulomb friction along the sidewalls. We obtain the solution by using the depth-integrated method. To verify the model, we perform dry granular dam break experiments. By changing the channel slope and deposition depth in the downstream channel, we can observe the different flow transition behaviors in the length and time scales. We use the high-speed camera to record the process and apply the Particle Tracking Velocimetry method to capture the flow field. We adopt the material properties parameters from the calibration experiments and apply the parameters to the model. Finally, we compare the measured experimental results and the model predictions.