Modified moving particle method for modeling wave interaction with multi layered porous structures

Abstract

Modified Moving Particle method in Porous media (MMPP) is introduced in this study for simulating a flow interaction with porous structures. By making use of the sub-particle scale (SPS) turbulence model, a unified set of equations are introduced for the entire computational domain and a proper boundary treatment is suggested at the interfaces between fluid and the porous media. Similar to the Incompressible Smoothed Particle Hydrodynamic (ISPH) method, a robust two-step semi-implicit scheme is utilized to satisfy the incompressibility criterion. By means of the introduced model, different flow regimes through multi-layered porous structures with arbitrary shapes can be simulated and there is no need to implement calibration factors.The developed MMPP model is then validated via simulating the experiments of Liu et al. (1999) i.e. linear and turbulent flows through porous dams and the experiments of Sakakiyama and Liu (2001) i.e. wave overtopping on a caisson breakwater protected by multi layered porous materials. Good agreements between numerical and laboratory data present the ability of the introduced model in simulating various flow regimes through multi-layered porous structures. It is concluded that the turbulent flow is an important issue particularly at the interface between the free fluid and porous media and consequently, the accuracy of the previous Lagrangian models that were based on neglecting the turbulence effect can be improved significantly by means of the present model. In addition, to satisfy the continuity criteria in the SPH models, it is necessary to modify density of particles in accordance with their porosity.