Laboratory observations of the intermittent growth of edge waves with random incident waves

Xuelin Ding1, Giovanni Coco1, Robert T Guza2, Roland Garnier3, Colin Whittaker4, Robert A Dalrymple5, Zhangping Wei6, Pedro Lomonaco7, Paolo Blondeaux8 and Giovanna Vittori8, (1)University of Auckland, School of Environment, Auckland, New Zealand, (2)Scripps Institution of Oceanography, La Jolla, CA, United States, (3)Environmental Hydraulics Institute, Universidad de Cantabria, Santander, Spain, (4)University of Auckland, Civil and Environmental Engineering, Auckland, New Zealand, (5)Northwestern University, Department of Civil Engineering, Evanston, IL, United States, (6)Johns Hopkins University, Baltimore, MD, United States, (7)Oregon State University, Civil and Construction Engineering, Corvallis, United States, (8)University of Genova, Genova, Italy
Abstract:
Edge waves are infragravity waves trapped by refraction near the shoreline that propagate in the alongshore direction. For monochromatic incident waves, mode-zero subharmonic edge waves are more likely to grow. However, the role of random incident waves on the growth of edge waves remains unknown. Here we show that the growth of edge waves under random incident waves is intermittent, with edge waves present for limited periods of time and with smaller amplitudes than the monochromatic cases. We varied the frequency and directional spread and observed large variability in edge wave excitation. We also performed theoretical analysis and numerical simulations that are in line with our laboratory observations.
Back to: Nearshore Processes I