Effects of submersion depth on the dynamics and deposition of lock-release turbidity currents

This study investigates the influence of the submersion depth on the propagation dynamics and the deposition patterns of turbidity currents using the lock-release configuration. While previous studies have investigated the effects of submersion depth on conservative density currents, its impact on non-conservative, particle-laden currents has received comparatively less attention. To address this, we employed a set of high-fidelity numerical simulations based on the implicit large eddy simulation methodology to analyze the behavior of turbidity currents generated with different particle diameters and submersion depths. The analysis focused on key propagation parameters, including front position, front velocity, turbulent structures, and deposit patterns, enabling the estimation of the run-out distance. The results highlight a significant impact of the submersion depth on the evolution of the current and its depositional characteristics, demonstrating that increased submersion leads to extended run-out distances and changes in the deposit distribution. The evolution of coherent turbulent structures, such as Kelvin–Helmholtz billows and vortex shedding, was found to be strongly influenced by vertical confinement. Reduced confinement promoted the formation of larger, more organized turbulent structures, leading to higher shear stress near the bed and a more pronounced current separation. A threshold depth was identified beyond which further submersion produces diminishing changes, revealing an asymptotic behavior in flow characteristics and deposition patterns.