Numerical simulation of gravity driven turbidity currents using Computational fluid dynamics

Quantitative interpretation of sediment erosion, transportation and deposition processes are vital for a wide range of engineering workflows, including oil and gas exploration and civil engineering projects. The sediment transport process in the offshore regions are highly dependent on the environment of deposition and the topographic slope. In an aqueous medium, the major transportation of sediments happens due to gravity-driven variable density turbidity flows in which course to fine-grained particles are temporarily suspended within a fluid (usually water) and flow towards deeper water following the bathymetric gradient. This water saturated and sediment-laden transportation processes are known as turbidity currents and deposits formed are termed as turbidites. Generally, the turbidite deposits are formed due to slope failures in subaqueous conditions and composed by the layers of coarser to finer sizes particles that grade upward and formed graded beddings structure. Looking at the size, the study of such complex phenomena at a lab scale is limited to qualitative insights. This study scrutinizes the sediment transport due to turbidity currents in submarine regions which leads to the formation of deep-sea reservoir deposits. An Eulerian granular multiphase approach was adopted to model the fluid grain interaction using CFD. It is observed that apart from deposition phase, the sediment deposition took place even when the hydraulic head was not decelerated which is termed as the slumping phase during sediment transportation. The formation of fining upwards sequences is also studied in the inclined loose bed cases where a loose sand bed was patched near the marine bed. Different cases of intermixing and gradation of sediments (size variable) are simulated and critically examined to understand the depositional geometries of turbidite deposits. This study successfully demonstrates different models of sedimentary process in a subaqueous medium based on gravity and density variations and subsequent quantitative analysis of turbidite deposits. Copyright (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Functional Material, Manufacturing and Performances