Simulação numérica de transporte e depósito de sedimentos em suspensão em canal inclinado

Abstract

Gravity currents begin when two fluid bodies, with different densities, collides one against other, starting a relative movement in both, being these processes responsible for the transport of sediment from the continental shelf into the deep ocean and the marine construction relief. When the density of sediments transported by rivers exceeds the density of the ambient fluid, it can plunge and form a submerged current, called hyperpycnal plume. The purpose of this research is to investigate, using Direct Numerical Simulation (DNS), the plunge point dynamics of these currents, being employed the Immersed Boundary Method (IBM) to simulate the slope of the continental shelf. Are investigated the influence of the fall velocity of the particle, the initial concentration of suspended sediment, the declivity of the slope in plunge point formation and consequently in the dynamics of particle sedimentation. These results were compared qualitatively with experimental case found in the literature. Quantitative discrepancies were found arising from the use of two-dimensional configuration, and also uncertainty as to the experiment data. The two-dimensional cases showed that the initial concentration of particles and the slope of the platform directly affects the position of plunge point and so little the sediment deposits profile, as the fall velocity shows opposite behavior. The 2D configuration was inefficient for low Ri numbers, showing the necessity of three-dimensional simulations.