Environmental impact of tidal power in the Eastern Scheldt Storm Surge Barrier : Appendix D: The prediction of stone stability by a three-dimensional eddy resolving simulation technique

In this thesis, it is studied if the stability of a stone in a granular bed protection, can be predicted by the local output of a three-dimensional (3D) eddy resolving simulation technique. In earlier studies regarding stone stability, Reynolds-Averaged Navier-Stokes (RANS) models are used to determine the loads on the bed. In the resulting stability formulas, depth-averaged flow parameters are used, and the loads caused by turbulent fluctuations are taken into account by the modelled turbulent kinetic energy k. A load caused by turbulent wall pressures is never explicitly taken into account before. With the use of a 3D eddy resolving modelling technique, turbulence can be resolved to a certain extent, by which local parameters can be used to determine the load on the bed. This may result in a more accurate prediction of stone stability, and a more economical design method for granular bed protections. Due to the computational requirements needed for the most detailed eddy resolving modelling techniques, it is concluded that for the aim of assessing stone stability, Improved Delayed Detached Eddy Simulation (IDDES) is the most appropriate 3D eddy resolving modelling technique for now and the nearby future. This modelling technique is also applied in a study regarding the influence of tidal energy turbines in one of the gates of the Eastern Scheldt barrier. In this thesis, special attention is paid to develop a stability formula, which can be used to assess the stone stability in the highly turbulent flow region behind the Eastern Scheldt barrier, based on the output of these simulations.