Modeling turbidity currents: the effects of bottom morphology and fluid rheology over the final sediment deposits

Resumo

Turbidity currents are the main means by which sediments are transported across the ocean
floor and one of the principal mechanisms that leads to the formation of basins hosting oil reservoirs.

Detailed modeling of this phenomenon may offer new insights to help geologists to understand the de-
position mechanisms and the final stratigraphic form of the reservoir. As turbidity currents propagate

over the seafloor, they trigger the evolution of a host of topographical features through the processes of
deposition and erosion, such as channels and sediment waves. We aim at enhancing the understanding
of the underlying physics, with particular emphasis on the sediment deposition mechanisms. Numerical
experiments in setups intended to mimic, partially, as the bed morphology is not allowed to change,

close with experimental, have adopted. We present in this work a finite element residual-based varia-
tional multiscale formulation applied to the numerical simulation of particle-laden flows. We employ an

Eulerian–Eulerian framework to describe the flows in which the mathematical model results from the
incompressible Navier–Stokes equation combined with an advection-diffusion transport equation, where

viscosity depends non-linearly from the sediment concentration. Sediment-laden turbidity currents inter-
acting with irregular bottoms are investigated. The impact of bed morphology over turbidity currents

with viscosity varying with concentration is investigated through quantities of interest such as bottom

shear stresses and deposition. The spatial pattern of the deposition and its correlation with flow struc-
tures are the main focus of this analysis. Quantitative and qualitative observations of the currents are

captured in the experiments, we discuss the morphodynamics of the different scenarios for different bot-
tom bathymetry. Further studies may be carried out in order to constructing new concepts of bedforms

generation by density currents.