Print Email Facebook Twitter Nonlinear infragravity–wave interactions on a gently sloping laboratory beach Title Nonlinear infragravity–wave interactions on a gently sloping laboratory beach Author De Bakker, A.T.M. Herbers, T.H.C. Smit, P.B. Tissier, M.F.S. Ruessink, B.G. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2015-02-01 Abstract A high-resolution dataset of three irregular wave conditions collected on a gently sloping laboratory beach is analyzed to study nonlinear energy transfers involving infragravity frequencies. This study uses bispectral analysis to identify the dominant, nonlinear interactions and estimate energy transfers to investigate energy flows within the spectra. Energy flows are identified by dividing transfers into four types of triad interactions, with triads including one, two, or three infragravity–frequency components, and triad interactions solely between short-wave frequencies. In the shoaling zone, the energy transfers are generally from the spectral peak to its higher harmonics and to infragravity frequencies. While receiving net energy, infragravity waves participate in interactions that spread energy of the short-wave peaks to adjacent frequencies, thereby cre- ating a broader energy spectrum. In the short-wave surf zone, infragravity–infragravity interactions develop, and close to shore, they dominate the interactions. Nonlinear energy fluxes are compared to gradients in total energy flux and are observed to balance nearly completely. Overall, energy losses at both infragravity and short-wave frequencies can largely be explained by a cascade of nonlinear energy transfers to high frequencies (say, f . 1.5 Hz) where the energy is presumably dissipated. Infragravity–infragravity interactions seem to induce higher harmonics that allow for shape transformation of the infragravity wave to symmetric. The largest decrease in infragravity wave height occurs close to the shore, where infragravity–infragravity in- teractions dominate and where the infragravity wave is asymmetric, suggesting wave breaking to be the dominant mechanism of infragravity wave dissipation. Subject circulation/ dynamicsgravity waveswave breakingwave propertieswind waves To reference this document use: http://resolver.tudelft.nl/uuid:f7a7ae94-fcae-4d5d-918f-3764b4b7ebf1 DOI https://doi.org/10.1175/JPO-D-14-0186.1 Publisher American Meteorological Society Embargo date 2015-08-01 ISSN 0022-3670 Source Journal of Physical Oceanography, 45 (2), 2015 Part of collection Institutional Repository Document type journal article Rights (c) 2015 American Meteorological Society Files PDF jpo-d-14-0186.1.pdf 1.83 MB Close viewer /islandora/object/uuid:f7a7ae94-fcae-4d5d-918f-3764b4b7ebf1/datastream/OBJ/view