A mass conservation-based model for the run-out distance of planar monodisperse particle laden gravity currents

Abstract

Turbidity currents are defined as particle-laden gravity currents, in which sediment particles in suspension cause the density difference. Even tiny density differences can generate turbidity currents that travel over significant distances. The farthest distance reached by a turbidity current is often called the run-out distance and is measured with the turbidity current deposit. This study develops an original predictive model for the run-out distance by taking as reference numerical simulations of planar particle-laden lock-release mono-disperse gravity currents. Our model is based on the initially suspended mass conservation, requires fitting parameters from deposit density data, and is analogous to the advection length for surge flows. Through numerical simulations data to find the best fit of the model parameters, run-out distance model estimations are presented as a function of the particles settling velocity and compared with numerical and experimental data. Along with this investigation, it was also verified that the run-out distance does not change after a sufficiently large Reynolds number. Finally, we present the dimensional results on the prediction of the run-out distance in function of the particle diameter. The proposed model neglects erosion processes, assumes a smooth bottom boundary, and was calibrated primarily for laboratory-scale lock-release experimental conditions.