Particle-laden currents interacting with complex bottom topography: a numerical investigation

TL;DR

This study uses detailed 3D numerical simulations to analyze how bi-disperse turbidity currents interact with complex bottom features, revealing how obstacles influence sedimentation patterns of different particle sizes.

Contribution

It provides new insights into the effects of complex topography on turbidity current dynamics and sedimentation, using high-resolution DNS simulations.

Findings

Obstacles cause lateral deflection affecting coarse particle deposition.

Fine particles are influenced further downstream by topographical features.

The study enhances understanding of turbidity current interactions with seafloor topography.

Abstract

We conduct depth-resolved three-dimensional Direct Numerical Simulations (DNS) of bi-disperse turbidity currents interacting with complex bottom topography in the form of a Gaussian bump. Several flow characteristics such as suspended particle mass, instantaneous wall shear stress, transient deposit height are shown via videos. Furthermore, we investigate the influence of the obstacle on the vortical structure and sedimentation of particles by comparing the results against the same setup and but with a flat bottom surface. We observe that the obstacle influences the deposition of coarse particles mainly in the vicinity of the obstacle due to lateral deflection, whereas for the sedimentation of fine particles the effects of topographical features are felt further downstream. The results shown in this fluid dynamics video help us develop a fundamental understanding of the dynamics of turbidity currents interacting with complex seafloor topography.