WCSPH with Limiting Viscosity for Modeling Landslide Hazard at the Slopes of Artificial Reservoir

Abstract

Abstract:This work illustrated an application of the FOSS code SPHERA v.8.0 (RSE SpA, Milano, Italy) to the simulation of landslide hazard at the slope of a water basin. SPHERA is based on the weakly compressible SPH method (WCSPH) and holds a mixture model, consistent with the packing limit of the Kinetic Theory of Granular Flow (KTGF), which was previously tested for simulating two-phase free-surface rapid flows involving water-sediment interaction. In this study a limiting viscosity parameter was implemented in the previous formulation of the mixture model to limit the growth of the apparent viscosity, thus saving computational time while preserving the solution accuracy. This approach is consistent with the experimental behavior of high polymer solutions for which an almost constant value of viscosity may be approached at very low deformation rates near the transition zone of elastic-plastic regime. In this application, the limiting viscosity was used as a numerical parameter for optimization of the computation. Some preliminary tests were performed by simulating a 2D erosional dam break, proving that a proper selection of the limiting viscosity leads to a considerable drop of the computational time without altering significantly the numerical solution. SPHERA was then validated by simulating a 2D scale experiment reproducing the early phase of the Vajont landslide when a tsunami wave was generated that climbed the opposite mountain side with a maximum run-up of about 270 m. The obtained maximum run-up was very close to the experimental result. Influence of saturation of the landslide material below the still water level was also accounted, showing that the landslide dynamics can be better represented and the wave run-up can be properly estimated.

SPH Modeling of Water-Related Natural Hazards

“…The mixture model of [8], modified with limiting viscosity, was successfully applied in [9] to the analysis of a fast massive landslide at the slope of an artificial reservoir. The simulated case reproduced a two-dimensional scale laboratory test carried out in 1968 at the University of Padua reproducing in Froude similitude a characteristic cross-section of the Vajont artificial basin.…”

“…Therefore, several codes have been developed that use these HPC techniques to simulate complex hydraulic engineering problems of water-related natural hazards in reasonable execution times. Some examples are SPHERA for sediment transport [8] and landslides [9]; DualSPHysics to model the scouring of two-phase liquid-sediments flows [6,53]; and GPUSPH for simulating lava flows [74]. As explained in [89], due to the limitation of sequential computing and the high cost of increasing performance in sequential architectures, the era of sequential computing was replaced by the era of parallel computing.…”

“…In the field of dense granular flows, fast landslide dynamics can be properly simulated by accounting for the interactions with water (both pore water and stored water) that influences landslide deformability and run-out characteristics. Thus, complex multiphase flows can be simulated for investigating natural hazard related to a tsunami wave generated by a quick landslide at the slope of a reservoir [9][10][11][12][13]. Additionally, a fast shallow landslide triggered by intense rainfall at the slope of a hill represents the most common natural hazards in some areas of the world [14,15] and can be simulated with proper numerical modeling.…”

A Semi-Infinite Numerical Wave Tank Using Discrete Particle Simulations

“…Recently, SPH has been used for water-related natural hazard risk analysis such as fast landslides, tsunami waves, and flooding in complex geometry [18]. For example, Manenti et al [19] performed two-dimensional erosional dam-break simulation using SPHERA, a weakly compressible SPH code. The viscosity threshold determined by the convergence procedure was applied to the reference mixture model, and the results showed good agreement and stability, compared with the experimental results of landslide run-outs and maximum wave run-ups.…”

Computational Methods and Applications to Simulate Water-Related Natural Hazards

“…In order to explore different risk scenarios and potential risk-reduction options and to address hazard related uncertainty, the development of numerical models represents an important task in supporting emergency response agencies, water resource managers, insurance companies, and other decision-makers [2]. e application purpose of CFD modeling requires contextual attention to the output variables of predictive interest and their time and space scales, the level of accuracy required considering eventually real-time data assimilation, and computational efficiency demands [3,4]. e main aim of this special issue is to highlight the most recent advances in CFD modeling and its application related to water-related natural hazards and discusses future directions.…”