A SPH elastic-viscoplastic model for granular flows and bed-load transport

• Published in: Advances in water resources Vol. 111; pp. 156 - 173
• Main Authors: Ghaïtanellis, Alex, Violeau, Damien, Ferrand, Martin, Abderrezzak, Kamal El Kadi, Leroy, Agnès, Joly, Antoine
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2018; Elsevier Science Ltd; Elsevier
• Subjects: Bed load; bedload; Cohesive sediments; Computation; Dam failure; Effective stress; equations; Fluid mechanics; Granular materials; Granular rheology; Laplace equation; Liquid-solid transition; Mathematical models; Mechanics; methodology; Physics; Sediment transport; Shear stress; Smoothed particle hydrodynamics; Soil; Soil stresses; Soil treatment; Soils; Studies; Transport; Two dimensional models; Viscoplastic materials; water resources; Yield strength; Yield stress; Granular rheology; Smoothed particle hydrodynamics; Viscoplastic materials; Sediment transport
• ISSN: 0309-1708; 1872-9657
• DOI: 10.1016/j.advwatres.2017.11.007

•A novel multi-fluid model is proposed in WCSPH with semi-analytical boundary conditions.•An elastic-viscoplastic model is used and improved to model granular flows and bed-load transport.•The model is based on the granular properties of the material and is free of numerical parameters.•Experiments of granular soil collapse and bed-load transport experiments are well reproduced. An elastic-viscoplastic model (Ulrich, 2013) is combined to a multi-phase SPH formulation (Hu and Adams, 2006; Ghaitanellis et al., 2015) to model granular flows and non-cohesive sediment transport. The soil is treated as a continuum exhibiting a viscoplastic behaviour. Thus, below a critical shear stress (i.e. the yield stress), the soil is assumed to behave as an isotropic linear-elastic solid. When the yield stress is exceeded, the soil flows and behaves as a shear-thinning fluid. A liquid-solid transition threshold based on the granular material properties is proposed, so as to make the model free of numerical parameter. The yield stress is obtained from Drucker–Prager criterion that requires an accurate computation of the effective stress in the soil. A novel method is proposed to compute the effective stress in SPH, solving a Laplace equation. The model is applied to a two-dimensional soil collapse (Bui et al., 2008) and a dam break over mobile beds (Spinewine and Zech, 2007). Results are compared with experimental data and a good agreement is obtained.