Publication Date:
2022-05-26
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2016
Description:
Holes and channels were excavated in the surf zone on an ocean beach near Duck, NC,
and observations of the subsequent evolution of waves, currents, and the modified
seafloor were used to investigate nearshore dynamics. In one set of seafloor perturbation
experiments, deep holes with steeply sloping sides were excavated in the inner surfzone
seafloor. Observations of the infilling holes were used to make the first field estimates of
the surfzone morphological diffusivity, which describes the rate of seafloor smoothing by
downslope sediment transport. To improve the temporal resolution of bathymetric
estimates, a mapping method was developed to combine infrequent, spatially dense
watercraft surveys with continuous, spatially sparse in situ altimeter estimates of the
seafloor location. In another set of seafloor perturbation experiments, channels were
dredged across the surf zone with the propellers of a landing craft. Alongshore variations
in wave breaking caused by the perturbed bathymetry resulted in strong rip currents in the
channels under some conditions, whereas alongshore currents bypassed the channels
under other conditions. The dynamics of the circulation response for changing wave
forcing, bathymetry, and tidal elevation are investigated using the observations, a
numerical model, and a parameter based on wave properties and bathymetry.
Description:
This work was supported by the Assistant Secretary of Defense for Research and
Engineering, the National Science Foundation, the Office of Naval Research, the WHOI
Coastal Ocean Institute, the National Science Foundation Graduate Research Fellowship
Program, and a National Defense Science and Engineering Graduate Fellowship.
Keywords:
Hydrodynamics
Repository Name:
Woods Hole Open Access Server
Type:
Thesis
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