Influence of Orientation and Arrangement of Structures on Tsunami Impact Forces: Numerical Investigation with Smoothed Particle Hydrodynamics

Abstract

This paper explores the influence of onshore structures' orientations and arrangements during tsunami impact using the numerical method of smoothed particle hydrodynamics (SPH). Observations from previous tsunami events often reveal variation in the damage and survivability of impacted similar structures. Such variation can be due to shielding effects and other interactions that occur when the tsunami wave is incident upon an urbanised location. The SPH model used in this work was first validated against previous experimental results and was then used to explore the resulting hydrodynamic behaviour to a level of detail hitherto unobtainable from physical experiments. Groups of three and five structures were modelled with varying spatial separation and orientation to the incoming tsunami bore, characterised by the wake clearance angle (A) and the rotation angle (R), respectively. The results reveal significant reductions in total force on a structure can be made via strategic spatial positioning and orientation. Such reductions may mean the difference between superficial damage and wholesale structural collapse and allow the development of more resilient structures in tsunami-prone regions.

Tsunami-like Flow-Induced Forces on the Landward Structure behind a Vertical Seawall with and without Recurve Using OpenFOAM

“…Regularly applied methods that have been used in the tsunami interaction studies are the Finite Volume method [45][46][47], the Arbitrary Lagrangian-Eulerian method [48], the Finite Element method [49], the coupled FEM and meshless method [50,51], the coupled FEM and FVM methods [52] and particle-based methods, such as the Smoothed Particle Hydrodynamics [53], the Moving Semi-Implicit method and the Meshless Local Petrov Galerkin method [50,54]. With increasing computational resources in recent decades, numerical simulations can provide a more in-depth understanding of flow interaction processes [55,56]. From the range of available methods, the open-source FVM solver OpenFOAM is applied in the present study to investigate the interaction processes between tsunamis and inland structures in the presence of seawalls.…”

Mitigating tsunami effects on buildings via novel use of discrete onshore protection systems

“…Cunningham et al (2014) has also demonstrated the suitability of SPH modelling to predict the tsunami wave force on discrete, non-orthogonal structures in comparison to the corresponding experimental results by Zhang (2009). More recently, Pringgana et al (2021) confirmed that the SPH numerical modelling using DualSPHysics was capable of predicting the tsunami wave and structure interaction for an array of structures reproducing and extending the experiments conducted in a large wave basin by Thomas et al (2015).…”

“…Generally, the SPH pressure distribution over a surface of a structure is measured by numerical probes. Pressures measured on a surface can be multiplied by the area of structure's surface to obtain force, as described in Pringgana et al (2021). The inter-particle spacing of a group of measuring pressure probes and their distances from the surface of structures are sensitive to the resulting numerical prediction so that prior sensitivity studies are required to achieve numerical pressure predictions comparable to the experimental data.…”

“…The ComputeForce tool has a similar function to the force measurement tool by using measuring probes placed on the front of certain surfaces. The use of measuring probes to determine force can be found in Cunningham et al (2014), Pringgana et al (2016 and Pringgana et al (2021). Other functionality available in DualSPHysics 5.0 is the FlowTool that can be used to calculate the number of fluid particles that enters or leaves a certain domain specified by the users.…”

“…Tomiczek et al (2016) used experiments to examine shielding effects of an array of regularly spaced structures showing that peak pressures of the breaking waves can be reduced by 30-70%. Pringgana et al (2021), using a smoothed particle hydrodynamics (SPH) numerical simulation approach, showed that the tsunami load reduction on a building is heavily influenced by its orientation and that of neighbouring structures to the oncoming tsunami wave direction. Moris et al (2021) studied the influence of a building array on tsunami-driven run-up loads and found that the number of rows of buildings providing shelter is an explanatory variable for the maximum wave run-up load reduction.…”