Cohesive sediments exist as flocs of different sizes, which are built and destroyed through flocculation processes including both aggregation and breakup. Recent observations showed that Langmuir circulations that span the entire water column are related to intense sediment resuspension on the shallow shelf. Combining a size-resovling flocculation model with a large-eddy simulation model, we found that the aggregation and breakup rates can be enhanced or suppresed by turbulence. The animation below shows the sediment resuspension when Langmuir circulations occupy the water column.

Reference: Liu et al., 2019

[a] Nomalized vertical velocity, [b] normalized turbulent kinetic energy dissipation rate, and [c] normalized suspended sediment concentration in Langmuir turbulence (h=15m)