Hydrodynamics of an Innovative Discontinuous Double Breakwater, Mixed Modeling: 2D Flume Physics and 3D Digital Modelling

EasyChair Preprint 990

Abstract

An improved design method of shore parallel discontinuous submerged breakwaters with optimal geometry is presented. In particular, the effect of breakwater openings on hydrodynamic conditions around the structures is experimentally and numerically investigated. The challenge of this study is not only validating the experimental findings using numerical methods but also investigating further alternative forms and geometries which cannot be reproduced in the wave flume. This research concerns a submerged coastal structure made out of two shore-parallel rouble mound breakwaters with openings (channels) whose main objective is to limit wave-induced set-up by pumping out and generating transverse seaward flows. Our wave flume (Figure 1), extended 31m in cross-shore and 1.8m in along-shore direction, is equipped with a piston type wavemaker and the sea-bed is represented by a 1/36 scale distorted movable bed model. The main experimental results concern the hydrodynamic conditions in the channels, where offshore-oriented currents are presented. The numerical modeling is performed using OpenFOAM software. After the validation of experimental findings, a second task consists in expanding the structure in along-shore direction. The main objective is to assess the bias committed by the wave flume configuration. Thus, the simulations are realized with identical bathymetry, but for models four and eight times wider than the original one and with either a finite or an infinite structure. The results show that the local three-dimensional flow always exists and is negligibly influenced by reflexions on the wave flume walls. The initial physical model can therefore be considered as the representation of an infinite structure.

Keyphrases: Hydrodynamics, OpenFOAM, breakwater, coastal structures, wave flume

@booklet{EasyChair:990,
  author    = {Christian Raffourt and Charlie Vergnet and Vasileios Afentoulis and Philippe Bardey},
  title     = {Hydrodynamics of an Innovative Discontinuous Double Breakwater, Mixed Modeling: 2D Flume Physics and 3D Digital Modelling},
  doi       = {10.29007/ngq6},
  howpublished = {EasyChair Preprint 990},
  year      = {EasyChair, 2019}}