http://scholars.ntou.edu.tw/handle/123456789/21186
Title: | Modeling two-dimensional infragravity motions on a fringing reef | Authors: | Shih-Feng Su Gangfeng Ma |
Keywords: | Infragravity waves;Edge waves;Circulation;Fringing reef | Issue Date: | Apr-2018 | Publisher: | ELSEVIER | Journal Volume: | 153 | Start page/Pages: | 256-267 | Source: | Ocean Engineering | Abstract: | This study investigates infragravity motions on a two-dimensional fringing reef with a concave topography using a wave-resolving nonlinear Boussinesq wave model. The effect of bathymetric nonlinearity on spatial variations of infragravity waves is studied from shore-normal incident random waves. The model is first verified from cross-shore/alongshore significant wave height, wave setup and infragravity wave height measured in laboratory experiments. The modeled velocity is further examined to elucidate the infragravity-wave current field. Wavenumber-frequency velocity spectra show that cross-shore infragravity motions are controlled by the leaky waves, while alongshore infragravity motions exhibit edge waves characteristics. Additionally, high-mode edge waves prevail on the entire infragravity frequency band while low-mode edge waves are dominant at very low frequencies. Furthermore, the model results illustrate the spatial and temporal variability of wave-induced nearshore currents, alongshore and cross-shore flows accompanying with circulation cells and rip currents. The infragavity-wave current field is nearly identical to the mean current field and the circulations develop at the same spatial scale as the reef flat. |
URI: | http://scholars.ntou.edu.tw/handle/123456789/21186 | DOI: | 10.1016/j.oceaneng.2018.01.111 |
Appears in Collections: | 海洋工程科技學士學位學程(系) |
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