A COMPARISON OF WAVE-DOMINATED
CROSS-SHORE SAND TRANSPORT MODELS
Wing Hong Wong
E-mail:
w.h.wong@student.utwente.nl
Graduation Date:
31 May 2010
Graduation committee:
Jan S. Ribberink
Jolanthe J.L.M. Schretlen
Kathelijne M. Wijnberg
Due to the increasing amount of activities in the coastal areas, it is
becoming more and more important to be able to predict the
morphological developments in these areas. For this purpose
many sand transport models have been developed. Most of the
existing cross-shore sand transport models for coastal areas are
based on data measured in experiments conducted in oscillatory
flow tunnels (OFT). In these experiments boundary layer
streaming, which is a steady current induced by surface waves,
does not occur. Boundary layer streaming could be relevant for
cross-shore sediment transport, since the current is present close
to the bed and it is constant in one direction. In the recent years
three practical wave-dominated cross-shore sand transport models
have been developed that include boundary layer streaming. The
objectives of this study are i) identifying which model is the most
suitable for predicting wave dominated cross-shore sand transport
and ii) gaining more understanding of the influences of the
boundary layer streaming on the model performances under
surface wave conditions. To reach the objectives, the sand
transport predictions of the models of Nielsen (2006), Van Rijn
(2007) and a new transport model, the SANTOSS model (recently
developed by the University of Twente and the University of
Aberdeen), are compared with a large dataset of measured sand
transports in OFT experiments and surface wave experiments.
Furthermore, model intercomparisons are carried out to assess
which model gives the best performance in cross-shore sand
transport predictions under different conditions.
This study shows that only the model of Nielsen is not able to
perform well under surface wave conditions; the model
overestimates the sand transport under these conditions. The two
other model perform well under surface wave conditions.
Furthermore, this study shows that only the model of Van Rijn is
not able to perform well under acceleration skewed (sawtooth
shaped) wave conditions. The two other models are able to
perform well under these conditions. The most important difference
between the models is that among the three models, only the
SANTOSS model is able to perform well under rippled-bed
conditions and fine sand sheet flow conditions. The two other
models predict the sand transport into the wrong direction under
these conditions. The three figures below illustrate the
performances of the three models.
Nielsen
Van Rijn
SANTOSS
From left to right; the performances of the models of Nielsen, Van Rijn and the SANTOSS model. The X-axis represents the
measured sand transport; the Y-axis the calculated sand transport. The solid line indicates perfect agreement; the dashed
lines a factor 2 difference.
-1Water Engineering and Management