Wave, flow, and suspended sediment dynamics under strong winds on a tidal beach

Lingpeng Meng, Junbiao Tu, Xiaodong Wu, Sha Lou, Jun Cheng, Sergey Chalov, Xiangju Han, Daidu Fan

Research output: Contribution to journalArticlepeer-review

Abstract

Tidal beaches are shaped by intense wave-current interactions, leading to dynamic sediment erosion and accretion, which can be further complicated by strong winds. In this study, field observations were conducted on a tidal beach at the junction of Yangtze Estuary and Hangzhou Bay (China), to investigate the dynamics of wave, flow, and suspended sediment under strong winds. Observations were carried out synchronously at two sites on the middle and lower intertidal beach covering 4 semidiurnal tides (52 h) including a ∼20 h-long strong wind period. During the strong wind period, wave motions and flood currents were significantly enhanced, leading to a high combined wave-current bed shear stress (τcw). The wave-induced bed shear stress (τw) greatly exceeded current-induced bed shear stress (τc). Breaking waves generated turbulence at the surface and amplified the near-bed turbulent Reynolds stress (−uw‾ and −vw‾) at the shallow, middle intertidal beach. The intense hydrodynamics and turbulence kept sediments in suspension and hindered any settling, resulting in net erosion of the intertidal beach. These findings provide valuable insights into the complex interplay among waves, currents, and sediment dynamics under short-duration strong winds on tidal beaches. A key emphasis is placed on the significant role of breaking waves, underscoring the critical importance of their contribution to near-bed turbulence.

Original languageEnglish
Article number108799
JournalEstuarine, Coastal and Shelf Science
Volume303
DOIs
StatePublished - Aug 2024

Keywords

  • Bed shear stress
  • meso-Tidal beach
  • Sediment dynamics
  • Wave breaking

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