Wave-, wind-, and tide-driven circulation at a well-mixed ocean inlet

The effects of waves, wind, and bathymetry on tidal and subtidal hydrodynamics at unstratified, shallow New River Inlet, NC, are evaluated using field observations and numerical simulations. Tidal flows are ebb-dominated (-1.5 to 0.6 m/s, positive is inland) inside the main (2 to 5 m deep) channel on the (1 to 2 m deep) ebb shoal, owing to inflow and outflow asymmetry at the inlet mouth. Ebb-dominance of the flows is reduced during large waves (> 1 m) owing to breaking-induced onshore momentum flux. Shoaling and breaking of large waves cause depression (setdown, offshore of the ebb shoal) and super-elevation (setup, on the shoal and in the inlet) of the mean water levels, resulting in changes to the cross-shoal pressure gradient, which can weaken onshore flows. At a 90-degree bend 800-m inland of the inlet mouth, centrifugal acceleration owing to curvature drives two-layered cross-channel flows (0.1 to 0.2 m/s) with surface flows going away from and bottom flows going toward the bend. The depthaveraged dynamics are tidally asymmetric. Subtidal cross-channel flows are correlated (r2 > 0.5) with cross-channel wind speed, suggesting that winds are enhancing and degrading the localcurvature- induced two-layer flow, and driving three-layer flow.

Grantor dc:publisher

Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

Year dc:date.issued

2017

Author dc:creator

• Wargula, Anna E.

• Hydrodynamics
• Waves
• Tides
• Winds

Language dc:language.iso

en_US

DOI

10.1575/1912/9059

OAI identifier oai:identifier

oai:darchive.mblwhoilibrary.org:1912/9059