Validation and Optimization of a Design Formula for Stable Geometrically Open Filter Structures

Granular filters are used for protection against scour and erosion of base material. For a proper functioning it is necessary that at the interfaces between the filter structure, the subsoil and the water flowing above the filter structure no material will be transported. Different types of granular filters can be distinguished, this paper...

Stable and unstable coastal inlet cross-sectional behaviour

A review will be presented of the theory behind stable and unstable coastal inlet cross-sectional behaviour. The theoretical findings behind stable coastal inlet cross-sectional behaviour will be reviewed, analysed and confronted with empirical findings, leading to some unresolved questions. Second, seasonal variations will be shown to induce...

Bifurcation dynamics and avulsion duration in meandering rivers by one-dimensional and three-dimensional models

At river bifurcations, water and sediment are divided over two branches. The dynamics of the bifurcation determine the long-term evolution (centuries) of the downstream branches, potentially leading to avulsion, but the dynamics are poorly understood. The long-term evolution can only be studied by one-dimensional models because of computational...

Report on measurements: Pressure and velocity fluctuations around a granular-bed element

The second chapter describes the general methodology of the research. It presents the key questions about the entrainment of stones from granular filters that are as yet unanswered. It also describes the aspects that are being regarded in the analysis in this report. In chapter 3 the measuring set-up is described. The following two chapters...

Bowthrusters and the stability of a riprap revetment

Because of problems with the design guidelines produced by PIANC for armoured slopes under attack by bowthrusters, additional work has been done in the Netherlands. On the basis of this work computational rules have been developed. However, because of the increase of bowthruster power, more detailed knowledge is needed on the effect of a...

Pressure Sensors and Filtering Techniques for Stone Stability Assessment

This report is structured as follows: In chapter 2 the importance of wall pressures with respect to the present research is described. The literature on wall pressures that was used, and some general features of wall pressure fluctuations are subsequently described in chapter 3. Chapter 4 deals with the pressure sensors. It begins with a brief...

Stability of stones in the top layer of a granular filter: Literature survey

In order to understand the processes involved in damaging a granular filter, the behaviour of the separate particles it is made of must be known. The hydrodynamic forces on the particles are very important for understanding this behaviour. These forces have been examined by many researchers. Chapter 2 deals with that aspect. The characteristics...