A New Symmetrical Unit for Breakwater Armour: First Tests

A new and symmetrical single layer armour unit, the crablock, has been designed in the UAE. One breakwater was reconstructed with crablock, but very limited testing had been performed. Just to become more acquainted with this new unit, pre-competitive research at a university has been performed, which is the subject of this paper. Being a new...

Two-Dimensional Wave Overtopping Calculation over a Dike in Shallow Foreshore by SWASH

In this paper, a numerical wave-flow model SWASH, based on non-linear shallow water equation with non- hydrostatic pressure, is applied to the estimation of wave overtopping over a dike in shallow foreshores. First sensitivity analysis is conducted to see the influence of wave generation, grid size, time window and bottom friction by one...

Wave overtopping reduction by seadike crown-walls in Vietnam

Extensive laboratory experiments were carried out to investigate wave overtopping on seadikes with (vertical) crown-walls in Vietnam. It is shown that the wave overtopping reduction by walls is inadequately, although rather complexly, described by TAW-2002. A new approach has been developed, which can straightforwardly be incorporated in the...

Wave overtopping resistance of grassed slopes in Viet Nam

The Simulator was applied to test the resistance against wave overtopping of grass covered dike slopes in Viet Nam. Observation and measurement during destructive tests were performed to investigate the development process of damage induced by overtopping flow. Damages were likely to be initiated at transition of either geometry or materials, at...

Wave overtopping resistance of grassed dike slopes in Vietnam

The resistance of various grassed slopes against wave overtopping has been appraised by means of the Wave Overtopping Simulator in situ for a couple of years in Viet Nam. Destructive test results show that a dike slope covered with grass could suffer a certain overtopping discharge not smaller than 20 l/s per m. During testing it was difficult...

Wave overtopping simulator tests in Vietnam

Sea dikes in Viet Nam have been built up during a long history. Every year, about 4 to 6 storms attack the coast and cause severe damages of the sea dikes. Till now, little is known about strength and stability of the inner slope covered with grass under impacts of wave overtopping during storm surges. Destructive tests have been performed with...

Riprap stability on the inner slopes of medium-height breakwaters

Medium height breakwaters are subjected to a considerable amount of overtopping. This implies the armour on the inner slope has to stable against overtopping waves. Existing equations do lack some basic understanding of the process of starting up movement of rock on the inner slopes. In order to get more insight into this phenomenon a special...