The effect of small density differences at large confluences

Confluences are special, complex elements within river systems which have been subject of much research. However, little attention has been given to the effects of density differences in confluences. The aim of this research is to see when and how density differences are important in confluences with respect to other occurring flow structures....

Resistance of submerged groynes

Groynes are commonly used in the major rivers in the Netherlands. They confine the flow of the river to a main channel but also act as resistance element once submerged and in that way influence the stage discharge relationship of the river. Several formulas exist describing groynes as a drag resistance. Another possible way of determining their...

Turbulence in the wake of a roughness patch

Little research was done in the past concerning the propagation of three dimensional effect in shallow wake flow caused by a roughness patch. Today’s research on related subjects is dominated by emerging obstructions in shallow water where the flow can be assumed as (quasi) two dimensional. However the relevance of a submerged obstruction with...

Turbulence in shallow jet flows

The general flow pattern of an open channel flow, downstream of a width restriction by two artificial dams, is analysed. A physical Froude-scaled model, under hydraulic rough conditions, with a significant large Reynolds number is used to ensure turbulent flow. Upstream of the dams the flow is uniform in transverse direction, in between and...

The use of pile groynes to reduce sediment exchange between river and harbour

The use of pile groynes to reduce sediment exchange between river and harbour Introduction To reduce siltation in harbours located in rivers or waterways in order to decrease the high costs of dredging and maintenance of its basins, a need of searching measures to decrease the sediment exchange between river and harbour arises. Research One of...

Particle tracking velocimetry in ondiep-water menglagen

In onderhavige studie is de meettechniek "Particle Tracking Velocimetry" (PTV) toegepast ten behoeve van het onderzoek naar ondiepe waterstromingen. Het doel van het onderzoek was de meettechniek beschikbaar te krijgen voor studies aan ondiep-waterstromingen en de geschiktheid van de methode voor het meten van grootschalige structuren aan te...

Research on a shallow water mixing layer: Derivation of one-dimensional mixing layer model and spatial correlation measurements

A shallow water mixing layer is a flow pattern which develops between two adjacent streams with a different velocity. The horizontal dimensions of a shallow water mixing layer are much larger than the depth. This results in a turbulent process in the mixing layer which is characterized by the presumable presence of two distinct turbulent length...