Hydrodynamic effects of primary vessel waves in a semi-closed groyne field

Abstract

The port of Rotterdam is one of the most important ports in Western Europe and via the 'Nieuwe Waterweg' it provides maritime trading between the large hinterland and the rest of the world. To provide port access for the large vessels, the channel and port basins need to be dredged regularly. At the same time, in other locations, sediment is required to fill erosion holes, develop natural habitats and improve water quality. Different stakeholders joined forces to acquire more knowledge about managing the sediment in the system. This resulted in the project called 'Proeftuin Sediment Rijnmond'(PSR). One of the pilot projects of PSR is located in the ’Nieuwe Waterweg’ where a longitudinal dam is constructed between groynes to study the effects on nourished sediment. The location used for this pilot is called Groyne Field 9. At the same time, the area around Groyne Field 9 is involved in another project called the 'Groene Poort'. This project focuses on natural development in the areas between groynes. The research in this thesis contributes to knowledge acquirement for the various projects. It studies the effect primary vessel waves have on the hydrodynamic behaviour in the semi-closed Groyne Field 9.

The study answers the research question: How can primary vessel waves impact the hydrodynamics in the semi-closed Groyne Field 9 in the 'Nieuwe Waterweg' and how can the hydrodynamic conditions be modified with different structural layout designs? Two different approaches are used to answer the question. First, a data analysis is conducted using 2 relevant data sets and secondly, a numerical model is developed to be able to study the topic in a more controlled environment.

The First part of the research analyses two data sets simultaneously. Water level and velocity measurement data obtained inside the groyne field is combined with Automated Identification System data (AIS data), which contains velocity, location and more information about sailing vessels. Combining these data sets enables the possibility to study the effect of the vessels' characteristics on the water level in Groyne Field 9. A regression analysis is carried out which results in an equation that shows the correlations of all parameters. The most significant parameter influencing the severity of the primary vessel wave is the sailing velocity. Other important parameters that cause water level drawdown are the length, width and draught of the vessel.

In the second part of the research, a numerical model of sailing vessels in the 'Nieuwe Waterweg' is developed in Delft3D Flexible Mesh software. This can be used to analyse the hydrodynamic effect on the groyne field in a controlled way. To simulate vessels passing through the waterway, a local atmospheric pressure field is used. This pressure field simulates the vessels’ hull and by moving the pressure field through the numerical domain, a primary wave is modelled. To research the effect of primary vessel waves on the semi-closed groyne field, various simulations are conducted and analysed which can be distinguished by two sets of simulations...