Multiphase Flow Modelling Using Smoothed Particle Hydrodynamics: Considerations on Sediment Transport

Environmental applications of multiphase flows include sediment transport and phenomena involving air–water interfaces that are dealt with as either free-surfaces or physical transition regions. Arguably, no need for applying interface tracking or capturing techniques is one of the incentives to work on the Lagrangian particle methods such as Smoothed Particle Hydrodynamics (SPH) as an alternative to better established Eulerian approaches. The meshless nature of SPH may also offer some advantages for fluid–solid interaction problems such as flow-induced bed scour in river hydraulics or coastal engineering. Upon spatial discretisation using interpolation points, or particles, the flow dynamics in SPH is represented by a system of ordinary differential equations for particles’ advection and the evolution of carried-on quantities (mass, momentum, phase indicator, etc.). In the paper, we briefly recall some basic features of SPH in terms of its capacity to describe physical phenomena together with numerical aspects and issues. As a particular SPH application of interest in environmental hydraulics, we report some results on model ingredients for sediment transport using the two-fluid approach (together with experimental validation attempts) and discuss next steps towards a complete account for free surface effects and the bed scour.