Non-linear wave generation and absorption using open boundaries within DualSPHysics

The present work introduces the implementation of wave generation and wave absorption of non-linear, long-crested regular and irregular waves in the WCSPH-based (Weakly Compressible Smoothed Particle Hydrodynamics) DualSPHysics solver. Open boundaries are applied here for both wave generation and absorption. These boundaries consist of buffer zones, on which physical quantities are imposed, or extrapolated from the fluid domain using ghost nodes. Several layers of buffer particles are used to create an inlet and an outlet, where the horizontal component of the orbital velocities, surface elevation and pressure can be imposed from any external source or extrapolated from the fluid domain. This allows the creation of a numerical wave flume with a length of one wavelength. Reflections within the fluid domain are successfully mitigated using a velocity correction term at both inlet and outlet. The implementation is validated with theoretical solutions, in terms of water surface elevation, wave orbital velocities, and dynamic pressure. The model proves to be capable of propagating waves with less than 5% reflection, and RMSE errors on physical quantities lower than 4.3%. The application of open boundaries proves to be an accurate method to generate and absorb non-linear waves within a restricted domain. © 2019 Elsevier B.V

SPH simulations of real sea waves impacting a large-scale structure

The Pont del Petroli is a dismissed pier in the area of Badalona, Spain, with high historical and social value. This structure was heavily damaged in January 2020 during the storm Gloria that hit southeastern Spain with remarkable strength. The reconstruction of the pier requires the assessment and characterization of the wave loading that determined the structural failure. Therefore, a state-of-the-art Computational Fluid Dynamic (CFD) code was employed herein as an aid for a planned experimental campaign that will be carried out at the Maritime Engineering Laboratory of Universitat Politècnica de Catalunya-BarcelonaTech (LIM/UPC). The numerical model is based on Smoothed Particle Hydrodynamics (SPH) and has been employed to simulate conditions very similar to those that manifested during the storm Gloria. The high computational cost for a full 3-D simulation has been alleviated by means of inlet boundary conditions, allowing wave generation very close to the structure. Numerical results reveal forces higher than the design loads of the pier, including both self-weight and accidental loads. This demonstrates that the main failure mechanism that led to severe structural damage of the pier during the storm is related to the exceeded lateral soil resistance. To the best of the authors’ knowledge, this research represents the first known application of SPH open boundary conditions to model a real-world engineering case.This research was funded by European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.: 792370.Peer ReviewedPostprint (published version

A Numerical Study of Fluid Flow in a Vertical Slot Fishway with the Smoothed Particle Hydrodynamics Method

Fishways have a great ecological importance as they help mitigate the interruptions of fish migration routes. In the present work, the novel DualSPHysics v4.4 solver, based on the smoothed particle hydrodynamics method (SPH), has been applied to perform three-dimensional (3-D) simulations of water flow in a vertical slot fishway (VSF). The model has been successfully calibrated against published field data of flow velocities that were measured with acoustic Doppler velocity probes. A state-of-the-art algorithm for the treatment of open boundary conditions using buffer layers has been applied to accurately reproduce discharges, water elevations, and average velocity profiles (longitudinal and transverse velocities) within the observed pool of the VSF. Results herein indicate that DualSPHysics can be an accurate tool for modeling turbulent subcritical free surface flows similar to those that occur in VSF. A novel relation between the number of fluid particles and the artificial viscosity coefficient has been formulated with a simple logarithmic fit

SPH simulations of real sea waves impacting a large-scale structure

The Pont del Petroli is a dismissed pier in the area of Badalona, Spain, with high historical and social value. This structure was heavily damaged in January 2020 during the storm Gloria that hit southeastern Spain with remarkable strength. The reconstruction of the pier requires the assessment and characterization of the wave loading that determined the structural failure. Therefore, a state-of-the-art Computational Fluid Dynamic (CFD) code was employed herein as an aid for a planned experimental campaign that will be carried out at the Maritime Engineering Laboratory of Universitat Politècnica de Catalunya-BarcelonaTech (LIM/UPC). The numerical model is based on Smoothed Particle Hydrodynamics (SPH) and has been employed to simulate conditions very similar to those that manifested during the storm Gloria. The high computational cost for a full 3-D simulation has been alleviated by means of inlet boundary conditions, allowing wave generation very close to the structure. Numerical results reveal forces higher than the design loads of the pier, including both self-weight and accidental loads. This demonstrates that the main failure mechanism that led to severe structural damage of the pier during the storm is related to the exceeded lateral soil resistance. To the best of the authors’ knowledge, this research represents the first known application of SPH open boundary conditions to model a real-world engineering case.European Union’s Horizon 2020 | Ref. Marie Sklodowska-Curie , n. 79237

A numerical study of fluid flow in a vertical slot fishway with the smoothed particle hydrodynamics method

Fishways have a great ecological importance as they help mitigate the interruptions of fish migration routes. In the present work, the novel DualSPHysics v4.4 solver, based on the smoothed particle hydrodynamics method (SPH), has been applied to perform three-dimensional (3-D) simulations of water flow in a vertical slot fishway (VSF). The model has been successfully calibrated against published field data of flow velocities that were measured with acoustic Doppler velocity probes. A state-of-the-art algorithm for the treatment of open boundary conditions using buffer layers has been applied to accurately reproduce discharges, water elevations, and average velocity profiles (longitudinal and transverse velocities) within the observed pool of the VSF. Results herein indicate that DualSPHysics can be an accurate tool for modeling turbulent subcritical free surface flows similar to those that occur in VSF. A novel relation between the number of fluid particles and the artificial viscosity coefficient has been formulated with a simple logarithmic fit.Ministry of Education, Science and Sport (Eslovenia) | Ref. P2-018

Composite modelling of the Pont del Petroli pier failure due to extreme sea waves during the winter storm Gloria

On January 20th, 2020, the storm Gloria causedthe collapse of the final part of the walkway that connected the seaward platform of the Pont del Petroli pier to the beach of Badalona (Spain). A stretch of about 15 meters fell into the sea due to strong impacts caused by a long-lasting wave action. A composite-modelling approach is proposed herein to reproduce the specific conditions that led to the failure of the pier. The goal of the work is to reconstruct the specific maximum wave conditionscaused by Gloria and to provide information on the ultimate resistance of the pier structural elements. The meshless SPH-based DualSPHysics code has been employed for a preliminary characterization of the loads exerted on each pier element by extreme wave conditions representative of Gloria. Numerical model results have been employed for the setup of the experimental campaign carried out in the large-scale wave flume facility CIEM at UPC in Barcelona. Bathymetric surveys carried out before and after the storm showed a radical change in the bottom bathymetry at the toe of the damaged area of the structure, with sand accretion and reduction of water depth from 10m to 8m, approximately. This heavy change is expected to affect the wave transformation and breaking right before the structure quite significantly. For experimental and numerical modelling, a wide range of extreme individual wave impacts have been generated by means of focused wave groups. The results from the physical model provide a new insight on the forces experienced by the pier during storm Gloria.This work was supported by the project GLORIA PID2020-115030RJ-I00 financed by MCIN/AEI/ 10.13039/501100011033 "Adquirir conocimientos sobre el riesgo de rebase para las zonas costeras urbanizadas".Postprint (published version

Restoring and rehabilitation of historical coastal asset with SPH

On January 20th, 2020, the storm Gloria caused the failure of the seaward platform and part of the footbridge of the Pont del Petroli pier at the beach of Badalona (Spain). A beam of about 15 m fell into the sea due to strong impacts caused by a long-lasting wave action. SPH modelling the wave-structure interaction provoked by the storm Gloria is here carried out. For its own meshless scheme and Lagrangian nature, SPH is ideal to model violent wave-structure interaction, characterized by heavy wave breaking, large discontinuity along the free surface and overtopping waves. The WCSPH-based DualSPHysics code has been employed for the scope. 2D and 3D modelling have been performed. The former one helped to understand whether a change in the foreshore profile and local water depth might affect the wave transformation and consequent wave-structure-interaction. The latter one was employed to offer a preliminary insight into the response of a propose restoration design alternatives. Both 2D and 3D modelling have been carried out with detailed representation of the structural elements (resolution about 1/10 of the platform and footbridge width) and reasonable computational time thanks to GPU computing.Dr. Corrado Altomare acknowledges funding from Spanish government and the European Social Found (ESF) under the programme ‘Ramón y Cajal 2020’ (RYC2020-030197-I / AEI / 10.13039/501100011033).Postprint (published version