Submerged breakwater influence on beach hydrodynamics: A 2DV approach

This master's thesis is written using data from experiments performed in the framework of the Human Capital and Mobility program of the European Union. Six universities work together to solve some of the unknown aspects related to the use of submerged breakwaters along sandy coasts. In this study data from 2DV tests carried out in Delft and Barcelona are used, from Delft are taken the morphological data and from Barcelona the velocity measurements. By varying the wave height and the wave period of the incoming wave the influence of these parameters on hydro- and morphodynamics are investigated. To analyse the performance of submerged breakwaters in beach profile morphodynamics the following parameters characterising beach changes are analysed; erosion volume, shoreline retreat, beachface slopes, developed profiles, bottom height change and cross shore transport rate. The influence of the wave height on the development of the profile is very clear, a larger wave height showing a larger change. The influence of the wave length is less evident and contrary to expected. A larger wave length is causing larger changes. The breakwater is in general reducing the changes of the beach profile, having a larger influence on the steeper and higher incoming waves. The validity of an energetic transport model (Bailard) and a hydro-morphodynamic numerical model (UNIBEST_TC) is verified for these experiments. The transport volumes calculated from the bottom profile changes measured in Delft are compared with transport volumes calculated from the velocity measurements in Barcelona, using the Bailard formula, and with transport volumes calculated with UNIBEST_TC. The transport volumes measured in Delft are in general larger than the calculated transport volumes. The quantity of the calculated transport volumes is restricted by the maximum values for the transport coefficients applied in the Bailard formula and UNIBEST_TC, taken from the literature.Hydraulic EngineeringCivil Engineering and Geoscience