Implementation of Open Boundaries within a Two-Way Coupled SPH Model to Simulate Nonlinear Wave–Structure Interactions

Tim Verbrugghe,Peter Troch,Andreas Kortenhaus,Vasiliki Stratigaki,J Domínguez,Corrado Altomare

doi:10.3390/en12040697

Tim Verbrugghe, Peter Troch + Show 4 more

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https://doi.org/10.3390/en12040697

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Journal: Energies	Publication Date: Feb 21, 2019
Citations: 26	License type: CC BY 4.0

Affiliation: Ghent University, Universidade de Vigo

Abstract

A two-way coupling between the Smoothed Particle Hydrodynamics (SPH) solver DualSPHysics and the Fully Nonlinear Potential Flow solver OceanWave3D is presented. At the coupling interfaces within the SPH numerical domain, an open boundary formulation is applied. An inlet and outlet zone are filled with buffer particles. At the inlet, horizontal orbital velocities and surface elevations calculated using OceanWave3D are imposed on the buffer particles. At the outlet, horizontal orbital velocities are imposed, but the surface elevation is extrapolated from the fluid domain. Velocity corrections are applied to avoid unwanted reflections in the SPH fluid domain. The SPH surface elevation is coupled back to OceanWave3D, where the originally calculated free surface is overwritten. The coupling methodology is validated using a 2D test case of a floating box. Additionally, a 3D proof of concept is shown where overtopping waves are acting on a heaving cylinder. The two-way coupled model (exchange of information in two directions between the coupled models) has proven to be capable of simulating wave propagation and wave–structure interaction problems with an acceptable accuracy with error values remaining below the smoothing length h S P H .

Highlights

Smoothed Particle Hydrodynamics (SPH), a mesh-less method that describes the fluid as a set of discrete elements, named particles, is typically computationally very intensive
This research tries to mitigate this problem statement by studying the possible reduction of the required SPH computational domain. This can be done by coupling SPH to a faster external numerical model which can deal with large computational domains
Development of accurate boundary conditions and the coupling of SPH solvers to external models are identified as key topics within the SPHERIC Grand Challenges to let SPH method attain a high level of maturity

Summary

Introduction

Smoothed Particle Hydrodynamics (SPH), a mesh-less method that describes the fluid as a set of discrete elements, named particles, is typically computationally very intensive. This research tries to mitigate this problem statement by studying the possible reduction of the required SPH computational domain. This can be done by coupling SPH to a faster external numerical model which can deal with large computational domains. This requires accurate and stable boundary conditions. Both the development of accurate boundary conditions and the coupling of SPH to external models are part of the SPHERIC Grand Challenges [2], which list the key issues to be addressed in order to make SPH a mature method.

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