An improved DebrisInterMixingFoam for debris flow simulation: numerical investigation and application

A 3D debris flow model-DebrisInterMixingFoam-is studied. An improvement is proposed to update the VOF field in each outer iteration to eliminate the time step dependency of the simulation results. The improved model is validated by a debris flow deposition on slope plane case. The results show that the improved model can give accurate results with larger time step. Then, the improved model is applied to two benchmark debris flow cases and the simulation of a real debris flow event. In all cases, the model results are favorably compared with the experimental data or field investigation data. The numerical results show that the improved model can achieve good accuracy for debris flow simulation after well calibrations of these two key parameters. Although the mixture phase model has its limitations to simulate the debris flow with phase interactions, it is still an effective option for the engineering application as there are only two key parameters to be calibrated in DebrisInterMixingFoam so that it is easy to be used to model debris flow.