A coupled DEM-CFD model to study the physical behavior of loose armor revetments in maritime waterways

Abstract

Revetments serve to protect a canal or river bank against erosion caused by natural and ship-induced waves and currents. A profound understanding of loads and resistances acting on revetments is indispensable for an economic and sustainable, but also safe revetment design. This paper presents a coupled CFD-DEM model (Computational Fluid Dynamics and Discrete Element Method) to study the physical behavior of loose armor stone revetments in maritime waterways. The waves and currents are modelled with a CFD add-on for the particle-based DEM software PFC3D. The DEM approach allows to simulate the shape, size and mass distribution and displacement of the individual armor stones realistically. DEM and CFD are coupled to capture the response of the armor stones to the hydraulic loads. In this paper, the model calibration and validation are presented using data derived from a full-scale flume experiment. The numerical model is compared to the flume tests where a slope is subjected to flow at different velocities. It can be shown that the implementation of revetment and hydraulic loads provides results that are consistent with the experimental data. Both flow velocities and armor stone displacements agree well between the physical and the numerical model. The herein presented study thus provides the basis for the application of the numerical model to more advanced stability analyses of revetments that are, e. g., subjected to wave and current attack.

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