Water movement over a horizontal bed and solitary sand dunes

In order to predict waterlevel changes in rivers due to floodwaves and local bedshapes for navigation, the local behaviour of the riverbed should be known . In many cases the bed of 3 river consists of dunes, which propagate downstream due to the sediment transport along the dunes . In this report mainly the watermovement but also the sediment transport along a dune is studied. The investigation consists of a theoretical and an experimental part. In the theoretical part a calculation of the flowfield above a dune is carried out us ing a computer model for the watermovement (ODYSSEE computer program of the Delft Hydraulics Laboratory, DHL). In the experimental part the mechanism of the local sediment transport along the dune is studied. The experimental set up consists of a solitary sanddune on a conveyor belt in a flume . The position of the dune is constant due to: conveyor belt velocity = propagation velocity of the dune . In this situation the flow field above the dune is measured using a Laser Doppler Anemometer (LOA), which is tested first in a uniform flov1 situation . The local sediment transport, which is known along the steady dune, is related to the local bed shearstress.Hydraulic EngineeringCivil Engineering and Geoscience

Watermovement over a horizontal bed and solitary sanddune

In order to predict waterlevel changes in rivers due to floodwaves and local bedshapes for navigation, the local behaviour of the riverbed should be known. In many cases the bed of a river ~onsists of dunes, which propagate downstraam due to the sediment transport along the dunes. In this report mainly the watermovement but also the sediment transport along a dune is studied. The investigation consists of a theoretica! and an experimental part. In the theoretica! part a calculation of the flowfield above a dune is carried out using a computer model for the watermovement (ODYSSEE computer program of the Delft Hydraulica Laboratory, DHL). In the experimental part the mechanism of the local sediment transport along the dune is studied. The experimental set up consists of a solitary sanddune on a conveyor belt in a flume. The position of the dune is constant due to: conveyor belt velocity = - propagationvelocity of the dune. In this situation the flowfield above the duneis measured using a Laser Doppier Anemometer (LDA), which is tested first in a uniform flow situation. The local sediment transport, which is known along the steady dune, is related to the local bedshearstress.Hydraulic EngineeringCivil Engineering and Geoscience