Erosion at transitions in landward slopes of dikes due to wave overtopping

Destructive wave overtopping tests have been performed at more than 20 dike sections in the Netherlands using the Wave Overtopping Simulator to simulate the overtopping waves. The tests show the combined behaviour of turf and substrate up to mean wave overtopping discharges of 75 ?/s per m, meaning wave volumes up to 5,500 ?/m with flow...

The influence of upstram turbulence on local-scour holes

Excessive local scour can progressively undermine the foundation of a structure. Because complete protection against scour is too expensive generally, the maximum scour-depth and the upstream slope of the scour hole have to be predicted to minimize the risk of failure. In 1961 a systematical research 'tY'ith respect to scour holes started in the...

Jet scour

This paper discusses scour without bed protection, such as propeller scour, two-dimensional horizontal, three-dimensional horizontal scour generated by free jets downstream of gates and outlets, two-dimensional vertical and three-dimensional vertical scour. The flow velocities in two- and three-dimensional propeller and free jets are briefly...

Ontgrondingen rondom brugpijlers en aan de kop van kribben

Het doel van het handboek ontgrondingen is een antwoord te geven op ontgrondingsvraagstukken zoals een ontwerper van waterbouwkundige constructies die tegenkomt. Verschillende deelstudies worden voor het afronden van dit handboek uitgevoerd. Het verifiëren van ontgrondingsformuies staat centraal in deze studies. Hier is de voorspellingskracht...

Analyses grass erosion in wave run-up and wave overtopping conditions

Within the framework of WTI, Research and Development of Flood Defence Assessment Tools (Wettelijk Toetsinstrumentarium), which is called in Dutch: WTI-2017 "Onderzoek en ontwikkeling landelijk toetsinstrumentarium", research was carried out to develop an erosion model for grass in the wave run-up zone consistent with the current model in use...

A hydraulic and morphologic criterion for upstram slopes in local-scour holes

Scour is a natural phenomenon caused by the flow of water in rivers and streams. Scour occurs naturally as part of the morphological changes of rivers and as result of structures man-made. Several types of scour can be distinghuished. Experience has shown that due to sand or flow slides or micro instabilities at the end of the bed protection,...

A study concerning the influence of the relative local turbulence on local-scour holes

Scour is the lowering of the sea or river-bed as a result of non-equilibrium sediment transport conditions and can be divided into several categories (Breusers and Raudkivi, 1991). Local scour, which may occur at the base of a structure because of the affected flow pattern, can severely endanger the stability of this structure. Many varieties of...