Ehsan Jafari Nodoushan - Assistant Professor of Civil Engineering, Bijar Branch, Islamic Azad University, Bijar, Iran
Mohanna Tajnesaie - Assistant Professor of Civil Engineering, Bijar Branch, Islamic Azad University, Bijar, Iran

The flow caused by a dam break usually develops towards the river or the plain flood. The downstream of the dam is usually a natural river where the bed is mobile and significant amounts of bed sediments are transferred downstream due to the non-continuous flow caused by the flood. Accurate prediction of complexities, involved in such a multiphase water-sediment system is still an important challenge for conventional mesh-based numerical models. Numerical methods, based on mesh-free Lagrangian approaches including Smoothed Particle Hydrodynamic )SPH (and Moving Particle Semi-implicit method (MPS), have provided a unique opportunity to deal with the deformation and fragmentation in these complex multiphase systems. This study develops and evaluates a mesh-free Lagrangian model based on a weakly-compressible MPS formulation for the simulation of two-phase rapid sediment transport. To model non-cohesive sediments, the sediment material is considered a non-Newtonian visco-plastic fluid, and an exponentially-regularized Herschel-Bulkley (H-B) rheological model in combination with Mohr-Coulomb yield criteria is employed. The capability of the developed numerical method is evaluated for two-phase sediment transport in a dam break on an erodible bed. Dam break flow over an erodible sediment bed for two geometrical setups (with dry and wet downstream) is considered. The comparison of the results with the available experimental measurements showed the capabilities of the proposed model in the accurate prediction of sediment and water profiles for this sample problem.

Moving particle semi-implicit method, Multiphase model, Exponential Herschel-Bulkley model, Erodible-bed dam break