Abstract
The impact of the seabed morphology on the
spatial variability of a strong tidal flow is investigated, at
both flood and ebb tides, using large-eddy simulations. The
simulations are performed over domains of about 0.5 km2,
with a spatial resolution of 0.34 m and using a detailed
bathymetry of 1 m resolution. For both simulations, the
presence of trails of reduced current velocity magnitude
and high turbulence level and of trails of accelerated flow
and low turbulence level is confirmed. These trails are
assumed to be originated from specific seabed landforms
or combinations of landforms that generate a high level
of turbulence at very localised positions. The locations
of the trails differ between flood and ebb tides, due to
the misalignment of the flow during those two periods
of the tide. On another note, the flow conditions notably
differ between flood and ebb, with a large zone of low
turbulence that appears during ebb tide, but not during
flood tide. This is due to the difference in the upstream
seabed morphology: a rough and shallow rocky plateau
during flood tide and a smoother and deeper seabed during
ebb tide.