Bowthruster-induced flow on the bottom of a vertical quay wall: A field measurement

During mooring operations, ships tend to make an extensive use of bowthruster in order to minimize the need for tug assistance. Jet caused by transverse thrusters directly impinges quay walls, and can cause scour on the bed, therefore threatening structural stability of quay walls. Presence of vertical quay walls induces reflection of...

The dynamic behaviour of hydraulic structures caused by wave impact loads: Enhancing the present design method in time and space

At this moment hydraulic structures are designed based on a simple method: the Dynamic Amplification Factor (DAF) method. This method does not consider the full dynamic interaction between the wave impacts, structure and water. The research project DynaHicS focusses on the dynamic behaviour of hydraulic structures, taking into account fluid...

Stability of the first row of an XblocPlus armour layer: A physical model study using Digital Displacement Analysis

XblocPlus is a new uniformly placed single layer armour unit, developed by Delta Marine Consultants (BAM Infraconsult). This report focuses on the stability of the first row of armour units, as this row is interlocked less than other rows. When the first row starts to slide, this is a big threat to the stability of the entire armour layer....

Nature-enhancing design of scour protection for monopiles in the North Sea

A combination of the growth of the offshore wind energy sector and the decline in both species richness and species abundance in the North Sea has inspired the goal to use the scour protection in wind farms as a means to enhance marine life. Present research has focused on general changes which are to be applied to benefit marine life. However,...

Stability of randomly placed log bed protections

Design criteria for the stability of rock filters on river beds (i.e. rock bed protection) are extensively researched and successfully applied in practice. The most common stability criteria are the Izbash and Shields criteria. These methods define a critical flow (Izbash) or parameter (Shields). Rijkswaterstaat (RWS) wants to explore a more...

Overtopping hazard reduction at Churchill Barriers, Scotland

Churchill Barriers, a series of four causeways in Orkney Islands, Scotland were constructed during Second World War and now serve and a critical link for South Ronaldsay and Burray to the Orkney Mainland. Due to their location and design, causeways are exposed to storm waves generated in the North Sea. During coastal storms, some waves are able...

Effects of ventilations on coastal structures with overhangs subject to wave impacts

Coastal structures with horizontal overhangs are built due to design constraints, but wave loadings substantially increase under these confined geometries. Vertical structure elements, such as steel gates, are vulnerable to damage caused by impulsive wave impacts, potentially exposing the coastal zone to flooding and erosion. Existing formulas...

Stability Optimisation of the top armour row of a breakwater with Xbloc^Plus units

The Xbloc^Plus (referred to as Xbloc+) is a new, uniformly placed single layer armour unit, developed by Delta Marine Consultants (BAM Infraconsult). Although a breakwater armour layer with Xbloc^Plus combines material saving and easy placement with increased stability, the transition between the armour layer and the crest is...

The relation between cobble revetments, sand and overtopping: A numerical approach with OpenFOAM®

OpenFOAM allowed the author to simulate a large number of scenarios in which the influences of cross-shore profile shape, cobble porosity, cobble diameter and layer thickness on wave overtopping were examined. Four validation runs and six simulations to map the sensitivity are compared with data from two physical experiments conducted in the...

Unravelling the sediment transport mechanisms in an artificial lagoon: Multi-modal sand transport analysis at the hard flood defence of Maasvlakte 2

The port of Rotterdam was full and new mooring locations were required to host the largest ships in the world. And if there’s no space to expand on land, why not create land in the sea? That is exactly what The Netherlands did by creating Maasvlakte 2. The construction of Maasvlakte 2 started in 2008 and was officially completed on May 22nd ,...

Wave loads on vertical structure with overhang: considering air influence

Wave impact on vertical structures with overhangs is studied. 3 research questions are addressed: 1. How does the entrapped air change during the process of wave impacts ? 2. How is the wave loading influenced by the presence of horizontal overhang ? 3. How is the wave loading influenced by the presence of air pocket?

Wave overtopping and scale effects: Experimental case study New Afsluitdijk

After more than 85 years, the iconic Afsluitdijk is in need of a reinforcement. During the latest safety assessment of Rijkswaterstaat the dike did not meet the standards at two components; the amount of wave overtopping (>10 l/m/s) and armour stability. This research goes into detail about the overtopping on the Afsluitdijk. In the new...

The influence of surface screens on morphology in side channels

Following from the programme Room for the River, side channels are created in the Netherlands. For their maintenance, alternatives to dredging vessels are needed because of nature development, such as surface screens, that use the flow itself to generate erosion. <br/>A field experiment using surface screens was executed at the small side...

Global Flood Hazard Reduction by Foreshore Vegetation

Global flood exposure simulations show that about 600 million people, of which 320 million in urban areas, are at risk to the impacts of global sea-level rise and changing storm intensity and frequency. Increasing availability of data and computational efficiency enables to assess flood hazard on a global scale. Implementation of salt marshes...

Stability of stones on mild slopes

The static stability of stones on mild slopes under wave attack is investigated in this research. The first part of the research is focused on reproducing the physical scale model tests regarding profile change of Kramer (2016) numerically with the model XBeach-G. The erosion profiles modelled with the bed-load transport formulas of Nielsen ...

Understanding the influence of beach morphology on the alongshore variance in wave run-up on an intermediate reflective beach, considering bars and cusps

The topic which is considered in this thesis is: understanding the influence of beach morphology on the alongshore variance in wave run-up on an intermediate reflective beach, considering bars and cusps. The focus of this thesis is laid inside the swash zone, in which the water motion is present of waves that run up and run down on a beach....

A new physics-based method for estimating the excess turbulence downstream of a structure

Erosion and sedimentation are natural processes that occur in natural flows.<br/>If the erosion is a threat for a structure, a bed protection is necessary to stop this process. A bed protection usually consists of relatively large stones.<br/>For calculating the required dimeter of the stones several formulae are available, of which the formula...

Rear-Slope Revetment Stability Approached by the Wave Overtopping Simulator: Experiments Regarding the Stability of Single-Layer Cube Revetment on Breakwater Crests and Rear Slopes

Contrary to a breakwater outer slope, rear-slope revetment does not have to withstand breaking waves. However, generally, an equal dimensioned revetment is used on both the inner- and outer slope. Although with low-crested breakwaters severe overtopping occurs, the application of similarly sized armour on both sides still results in an over...