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...

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...

Seabed scour by currents near platforms

The gravity platforms in the North Sea, sitting directly on granular seabeds, may be undercut by scour and need scour protection. Conventional methods of protections are developed for structures 1or 2 orders of magnitude smaller and seem unnecessarily conservative when scaled to these larger sizes. The reason is that some of the flow details...

Systematisch onderzoek naar twee en drie dimensionale ontgrondingen

Samenvattend rapport van alle twee- en drie dimensionale ontgrondingsonderzoeken uit de periode 1960-1970 bij het Waterloopkundig Laboratorium in opdracht van Rijkswaterstaat. De informatie uit de onderzoeken M648 en M863 zijn in deze rapporten samengevat, evenals de resultaten uit M847. (3 delen).

Time scale of two dimensional local scour

The time scale of local scour is of importance in many model studies of practical problems. The use of a time scale is justified by the similarity in experimental scouring holes under different conditions. A time scale is derived from experiments with a wide range of length scales, velocity scales and material scales. The influence of velocity...