Interaction between internal waves and a permeable seabed

Internal waves are abundant in stratified lakes and oceans in many parts of the world. Waves in short periods produce turbulent and mixing in the water body, while those associated with long periods have large amplitudes and sufficient energy to reach the pollutants on the seabed. In this study, a parametric approach is applied to analyze wave-induced soil response resulting from an internal wave action in a stratified two-layer water system. From which mathematical derivations are obtained for the wave-induced pore pressure and soil displacements.A new wave dispersion relationship containing water-wave-soil properties is also derived, which leads to wavelength modification of an internal or surface waves propagating on a poroelastic seabed. Wavelength varies not only with water depth and wave period, but is also modified by soil properties of a permeable bed.The mechanism of sediment resuspension is also discussed based on analytical solutions for the wave-induced soil displacements, instead of empirical equation as used in previous works. The numerical results calculated from these solutions provide a preliminary insight to quantify internal wave-induced sediment resuspension observed on a continental shelf slope in the ocean. Soil displacement on the seabed is estimated to reach 40 and 15 m in the horizontal and vertical directions, respectively, in the same order as observed in field condition in the northeastern South China Sea. (C) 2005 Elsevier Ltd. All rights reserved.