Wave-Induced Pressure Under an Internal Solitary Wave and Its Impact at the Bed

Internal Solitary Waves (ISW) of depression are known to cause significant resuspension and bed deformation during their passage. The underlying interplay between wave-driven hydrodynamics in the water column and the bed are yet to be fully understood. Given a characteristic stratification profile, observations of the induced-pressure hint at a potential bed failure during a wave episode. Employing a Fourier- nodal Galerkin method, we solve for the diffusion of the wave-induced pressure and assess the critical bed-normal pressure gradient responsible for particle movement. Likewise, we can also assess the induced shear stress as a possible mechanism for failure. In a similar context, we also examine the near-bed turbulent wake in the separating region in the lee of the wave. At sufficiently high ISW amplitude, the wave-induced BBL undergoes a global instability which produces intermittent vortex shedding from within the separation bubble. Using a 2D spectral multidomain penalty method with Re O(10⁵), we resolve for the vortex shedding episode expanding the scope of the induced-pressure and shear stress and characterizing their subsequent development. It can be argued that the resuspension of bottom particulate upon the passage of the ISW trough and BBL separation directly relates to the potential for bed failure. We aim to link both events under the context of a specific sediment transport model capable of describing a range of ISW environments studied in the field.