CFD, sensitivity analysis and optimisation to promote the formation of dunes

Abstract

In 2017, the ‘Kustpact’, a Dutch national agreement, was signed to develop the Dutch coast without damaging its ecosystem nor its aesthetics. Consequently, the formation and protection of coastal dunes have become a focal point for research and development. For this reason, based on the idea of Performance-Based Design (PBD), this Master thesis aims to investigate the impact of certain geometric design parameters of beach house configurations on wind turbulence for the purpose of widening the dunes.

A parametric design space was set up to easily automate Computational Fluid Dynamics (CFD) simulations for different purposes throughout this study. The sediment mobility estimation was the objective function for all simulations conducted. It is based on the difference of transport rate between two lines from the beginning of the plateau to the foot of the dunes. To simplify the parametric model, a Sensitivity Analysis (SA) was conducted to statistically identify the most influential parameters in the model. Afterward, the filtered parameters from the SA are used to build a surrogate model to detect the trends that result from combining the most influential parameters. Finally, a Surrogate-Based Optimisation (SBO) is conducted based on the former surrogate and using a Genetic Algorithm (GA). Three generations were run and used to increase the accuracy of the surrogate and predict an optimum solution for widening the dunes.

The study concludes on a list of design criteria to respect in order to widen the dunes mainly pertaining to the consistent position of the configuration relative to the dunes, the important overlap between houses and the larger wind-facing direction of the configuration.