Abstract
A physical parameter, µb, which was used to meet the forcing of primary short waves to be off-resonant before wave breaking, has been considered as an applicable parameter in the infra-gravity wave generation. Since a series of modulating wave groups for different wave conditions are performed to proceed with the resonant mechanism of infra-gravity waves prior to wave breaking, the amplitude growth of incident bound long wave is assumed to be simply controlled by the normalized bed slope, β b. The results appear a large dependence of the growth rate, α, of incident bound long wave, separated by the three-array method, on the normalized bed slope, β b. High spatial resolution of wave records enables identification of the cross-correlation between squared short-wave envelopes and infra-gravity waves. The cross-shore structure of infra-gravity waves over beaches presents the mechanics of incident bound- and outgoing free long waves with the formation of free standing long waves in the nearshore region. The wave run-up and amplification of infra-gravity waves in the swash zone appear that the additional long waves generated by the breaking process would modify the cross-shore structure of free standing long waves. Finally, this paper would further discuss the contribution of long wave breaking and bottom friction to the energy dissipation of infra-gravity waves based on different slope conditions.
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This work is sponsored by the Research Center of Ocean Environment and Technology under Grant No. D99-1500 and the Science Council under Grant No. NSC-99-2915-I-006-044.
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Lin, YH., Hwung, HH. Infra-gravity wave generation by the shoaling wave groups over beaches. China Ocean Eng 26, 1–18 (2012). https://doi.org/10.1007/s13344-012-0001-9
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DOI: https://doi.org/10.1007/s13344-012-0001-9