الفهرس 
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Abstract
The objective of this study is to have a better understanding of sediment
transport phenomena in the cross-shore direction under oscillatory water flows,
and to verify some of the existing models relevant to the present study. During
the study a mathematical model for describing sediment transport phenomena
under oscillatory water flows was developed.
The study focused on the sediment transport phenomena under the nonlinear
interaction between waves and net currents. The thesis consists of seven
chapters and five appendices. Experiments were carried out in the Large
Oscillating Water Tunnel of Delft Hydraulics, The Netherlands. The near-bed
orbital motion was simulated at full scale 1:1. The net current was
superimposed on waves partly in the direction of wave propagation and partly
in opposite direction of wave propagation. Three series of experiments were
carried out aimed at obtaining the side wall effect on the velocities and
sediment transport rates, invistigating the bedform regime under different
combinations of wave-current interaction and studying the sediment transport
phenomena under wave-current flows. Velocity measurements were carried out
using laser doppler system and electro-magnetic flow meter. Time-averaged
suspended sediment concentrations were measured by transverse suction
system. Net sediment transport rates were obtained by the mass conservation
techniques.
The data obtained from the experiments were used in the verifivcation of some of the existing models, which predict the net current profiles, timeaveraged
suspended sediment concentrations and sediment transport rates.
During the study a 1-0 mathematical model was developed for
describing the net current profile under waves and wave-current flows. The
model is capable of predicting the time-averaged and time-dependent sediment
concentrations in the suspension layer.
the conclusions from this study are summarized as follows:
A non-linear interaction occurs between the boundary layers of
waves and currents when a net current is superimposed on waves.
Waves make a considerable change to the net current velocities
especially inside the wave boundary layer.
The absolute magnitude and direction of the superimposed net
current on waves with respect to wave propagation have a significant
effect on the bedform regime and bedform dimensions.
The absolute magnitude of the net current and its direction with
respect to the wave propagation affect the absolute magnitude of the
reference bed concentration and the mixing length.
The net time averaged sediment transport rate increases with the
increase of the superimposed following net currents. The opposite takes
place in case of opposing net current superimposed on the same waves.
The developed mathematical model is capable of describing the
sediment transport phenomena in the cross-shore direction under waves
or combined wave-current flows ..
Recommendations for future research were also introduced.