scholarly journals Vertical structure of pore pressure under surface gravity waves on a steep, megatidal, mixed sand-gravel-cobble beach

2017 ◽  
Vol 122 (1) ◽  
pp. 153-170 ◽  
Author(s):  
Tristan B. Guest ◽  
Alex E. Hay
2008 ◽  
Vol 38 (11) ◽  
pp. 2341-2357 ◽  
Author(s):  
Steven J. Lentz ◽  
Melanie Fewings ◽  
Peter Howd ◽  
Janet Fredericks ◽  
Kent Hathaway

Abstract Onshore volume transport (Stokes drift) due to surface gravity waves propagating toward the beach can result in a compensating Eulerian offshore flow in the surf zone referred to as undertow. Observed offshore flows indicate that wave-driven undertow extends well offshore of the surf zone, over the inner shelves of Martha’s Vineyard, Massachusetts, and North Carolina. Theoretical estimates of the wave-driven offshore transport from linear wave theory and observed wave characteristics account for 50% or more of the observed offshore transport variance in water depths between 5 and 12 m, and reproduce the observed dependence on wave height and water depth. During weak winds, wave-driven cross-shelf velocity profiles over the inner shelf have maximum offshore flow (1–6 cm s−1) and vertical shear near the surface and weak flow and shear in the lower half of the water column. The observed offshore flow profiles do not resemble the parabolic profiles with maximum flow at middepth observed within the surf zone. Instead, the vertical structure is similar to the Stokes drift velocity profile but with the opposite direction. This vertical structure is consistent with a dynamical balance between the Coriolis force associated with the offshore flow and an along-shelf “Hasselmann wave stress” due to the influence of the earth’s rotation on surface gravity waves. The close agreement between the observed and modeled profiles provides compelling evidence for the importance of the Hasselmann wave stress in forcing oceanic flows. Summer profiles are more vertically sheared than either winter profiles or model profiles, for reasons that remain unclear.


1980 ◽  
Vol 99 (1) ◽  
pp. 163-183 ◽  
Author(s):  
Robert Bryan Long

A useful parametrical model for the vertical structure of the pressure field induced by wind blowing over a field of surface gravity waves is proposed. The model is a linear expansion in a set of empirical orthogonal functions, derived from a set of 110 complex pressure profiles computed according to the theory of Miles (1957), and provides a compact, quantitative description of those profiles. The model has been used as an element in the analysis of a body of experimental data on wave-induced atmospheric pressure fluctuations obtained by Snyderet al.(1980).


2008 ◽  
Vol 32 (9) ◽  
pp. 1696-1710 ◽  
Author(s):  
Eduardo Godoy ◽  
Axel Osses ◽  
Jaime H. Ortega ◽  
Alvaro Valencia

1973 ◽  
Vol 29 (3) ◽  
pp. 94-105 ◽  
Author(s):  
Ken Sasaki ◽  
Takashi Murakami

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