Review of smoothed particle hydrodynamics modeling of fluid flows in porous media with a focus on hydraulic, coastal, and ocean engineering applications.

This article provides a comprehensive review of Lagrangian mesh-free particle methods, particularly smoothed particle hydrodynamics (SPH) and its coupling with the discrete element method (DEM), for simulating fluid flow interactions with porous media in hydraulic, coastal, and ocean engineering. It distinguishes between macroscopic modeling—suitable for large-scale porous media with small solid particles using mixture theory and SPH—and microscopic modeling—appropriate for flows involving large solid particles using coupled SPH-DEM. The review addresses governing equations, interfacial boundary treatments, turbulence modeling challenges, and interaction mechanisms between fluid and solid phases, highlighting the strengths and limitations of each approach. A modeling framework is proposed to guide researchers in selecting appropriate mesh-free methods based on problem scale and porous media characteristics, emphasizing the prevalent use of 2D macroscopic models for engineering applications and the potential of 3D microscopic SPH-DEM models for detailed simulations. Future research directions include improving turbulence models, enhancing SPH-DEM coupling accuracy, and leveraging multi-GPU computing to overcome computational challenges in large-scale simulations.