Tetsuo Sakai, Hitoshi Gotoh


In almost all of the previous studies on the seabed configuration, the seabed configuration is classified based on the bottom shear stress, or Shields number. While, in the wave field, the wave-induced-water-pressure change can have a secondary effect on the sediment transport. The laboratory experiment on the seabed configuration under the coexistence of the oscillatory flow and the water-pressure change is conducted in this study, to investigate the effect of water-pressure change on the seabed regime classification. The existing region of various bed configurations, such as no-motion, bed-lad, suspension over ripple and sheet flow, changes with the change of the amplitude of water-pressure change. The ripple geometry, or flatness of ripple, are also affected by the water-pressure change. The mechanism of theses changes are discussed related to the lift force due to the porewater-pressure distribution in sand layer.


bed; bed configuration; wave pressure

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