Fluid-particle interaction regimes during the evolution of turbidity currents from a coupled LES/DEM model

Xie, Jiafeng; Hu, Peng; Pähtz, Thomas; He, Zhiguo; Cheng, Nian‐Sheng

doi:10.1016/j.advwatres.2022.104171

Cited by 10 publications

(34 citation statements)

References 93 publications

(99 reference statements)

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“…The lift force F l here follows Loth & Dorgan ( 2009) where C add = 0.5 is the added mass coefficient. Although the added mass force on particles in open channel sediment transport studies is generally considered to be unimportant (Schmeeckle 2014;Pähtz et al 2021), we found in our previous study (Xie et al 2022) that it cannot be neglected in TCs. Equation (2.17) assumes that particles are not in close proximity to one another.…”

Section: Discrete Element Methodsmentioning

confidence: 72%

“…These two models proceed independently, while the coupling of them at certain time intervals is implemented through the momentum exchange via CFDEMcoupling , developed by Kloss et al (2012). This coupled LES-DEM model has been widely validated and applied (Blais et al 2016;Yang et al 2018;Wang & Shen 2022), especially for TC simulations in our previous work (Xie et al 2022). In the following, the equations for the fluid phase are described in § 2.1, and the equations for the particle phase and the fluid-particle interaction forces are given in § 2.2.…”

Section: Methodsmentioning

confidence: 99%

“…The TC head refers to the foremost part of the current, the horizontal length of which is defined as 0.15 times the length of the TC. The definition of different head lengths (0.10 ∼ 0.20 times the length of the current) does not substantially affect the quality of the results of the head average forces (Xie et al 2022), however, its effect on the head auto-suspension index is unknown, which is explored in § 3.4.…”

Section: Numerical Set-upmentioning

confidence: 99%

“…Wildt et al (2021) employed an Eulerian-Lagrangian two-way coupled LES to simulate sediment plume development. Xie et al (2022) employed the analysis of the dispersed TC particle movement and particle acceleration/deceleration to understand the evolution of the TC. However, such particle-based research is currently rare, and the effects of the complex interaction between dispersed particles and fluids in TC are still far from being understood, which is beneficial for the understanding of auto-suspension.…”

Section: Introductionmentioning

confidence: 99%

“…In order to investigate auto-suspension from the perspective of fluid-particle interactions and the movement of individual particles, this paper employs the LES-DEM model to simulate lock-exchange TCs on inclined slopes. In comparison with our earlier study on TC evolution over a flat slope (Xie et al 2022), this present work focuses on the particle auto-suspension regimes and investigates the effects of different particle concentrations and slope angles on the auto-suspension regimes. We now additionally analyse the trajectories and spatial distribution of auto-suspension particles, the spatial characteristics of the forces acting on the auto-suspension particles and the auto-suspension index.…”

Section: Introductionmentioning

confidence: 99%

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Turbidity currents propagating down an inclined slope: particle auto-suspension

Xie

Zhu

et al. 2023

J. Fluid Mech.

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The turbidity current (TC), a ubiquitous fluid–particle coupled phenomenon in the natural environment and engineering, can transport over long distances on an inclined terrain due to the suspension mechanism. A large-eddy simulation and discrete element method coupled model is employed to simulate the particle-laden gravity currents over the inclined slope in order to investigate the auto-suspension mechanism from a Lagrangian perspective. The particle Reynolds number in our TC simulation is $0.01\sim 0.1$ and the slope angle is $1/20 \sim 1/5$ . The influences of initial particle concentration and terrain slope on the particle flow regimes, particle movement patterns, fluid–particle interactions, energy budget and auto-suspension index are explored. The results indicate that the auto-suspension particles predominantly appear near the current head and their number increases and then decreases during the current evolution, which is positively correlated with the coherent structures around the head. When the turbidity current propagates downstream, the average particle Reynolds number of the auto-suspension particles remains basically unchanged, and is higher than that of other transported particles. The average particle Reynolds number of the transported particles exhibits a negative correlation with the Reynolds number of the current. Furthermore, the increase in particle concentration will enhance the particle velocity, which allows the turbidity current to advance faster and improves the perpendicular support, thereby increasing the turbidity current auto-suspension capacity. Increasing slope angle will result in a slightly larger front velocity, while the effect of that on the total force is insignificant.

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Section: Discrete Element Methodsmentioning

confidence: 72%