Abstract
The present research aims at getting an understanding
of the process of dispersion of surface sediment in an
oscillatory boundary layer, which may represent an idealised
case of, for example, a stockpile area where excavated sediment
is stockpiled temporarily (or permanently). The process
is studied numerically, using a random-walk particle model
with the input data for the mean and turbulence characteristics
of the wave boundary layer picked up from a transitional
two-equation k–ω Reynolds averaged Navier–Stokes model
and plugged in the random-walk model. First, the flowmodel
is validated against experimental data in the literature. Then,
the random-walk dispersion model is run for different oscillatory
flow cases and for a number of steady flow cases for
comparison. The primary sediment grains of concern are fine
sediments (with low fall velocity), which would stay in suspension
for most of the time. Nevertheless, the dispersion of
neutrally buoyant and heavier particles that spend most of
their time in close vicinity to the bed are also discussed. The
numerical model results are compared with the results of a series of experiments carried out in an oscillating U-tunnel
facility. The results are found to be in general agreement both
qualitatively and quantitatively. In the last part of the study,
an example application of the present model for fine sand
dispersing in a wave boundary layer under storm conditions
is given.
Original language | English |
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Journal | Journal of Ocean Engineering and Marine Energy |
Volume | 2 |
Issue number | 1 |
Pages (from-to) | 59-83 |
Number of pages | 25 |
ISSN | 2198-6444 |
DOIs | |
Publication status | Published - 2016 |
Keywords
- Longitudinal dispersion
- Suspended sediment
- Oscillatory boundary layer
- Random-walk model
- RANS modelling
- U-tunnel experiments