Two- and three-dimensional Direct Numerical Simulation of particle-laden gravity currents

Espath, Luis; Pinto, Leandro C.; Laizet, Sylvain; Silvestrini, Jorge Hugo

doi:10.1016/j.cageo.2013.10.006

Cited by 41 publications

(66 citation statements)

References 19 publications

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“…The flow configuration is shown in Figure 1 and is exactly the same as in our previous work. 22 We assume a small volume fraction of the particles (typically less than 1%) so that interactions among the particles, such as hindered settling and/or particle inertia can be neglected. The coupling between particle and fluid motion is dominated by the transfer of momentum, rather than volumetric displacement effects.…”

Section: Problem Configuration and Governing Equationsmentioning

confidence: 99%

“…There has been an intensive effort to study those structures, with many experimental investigations, 3,7,[12][13][14][15] theoretical approaches, 16,17 and more recently with numerical investigations based on Direct Numerical Simulations (DNS). [18][19][20][21][22][23][24] Experiments 3,7,12 investigating a) s.laizet@imperial.ac.uk lobe-and-cleft patterns have typically imaged the gravity current from below, allowing the growth, merging, and bifurcation of the structures to be tracked. This analysis identified the origin of the instability as the unstable stratification generated as ambient fluid is overrun by the current head, subject to a frictional surface.…”

Section: Introductionmentioning

confidence: 99%

“…For turbidity currents with sedimentation, the highest Reynolds number simulated to date is 10 000 (Reynolds number defined with the half-size h of the vertical computational domain as a reference length). 22 Comparisons between 2D and 3D simulations for various Reynolds numbers were used to assess which quantities of interest for the geoscientist could be evaluated quickly with a 2D simulation. It was found that a 2D simulation is not able to predict accurately the main features obtained in a 3D simulation, with maybe the exception of the sedimentation rate for which a qualitative agreement can be found between the 2D and the 3D simulations.…”

Section: Introductionmentioning

confidence: 99%

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High-fidelity simulations of the lobe-and-cleft structures and the deposition map in particle-driven gravity currents

et al. 2015

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The evolution of a mono-disperse gravity current in the lock-exchange configuration is investigated by means of direct numerical simulations for various Reynolds numbers and settling velocities for the deposition. We limit our investigations to gravity currents over a flat bed in which density differences are small enough for the Boussinesq approximation to be valid. The concentration of particles is described in an Eulerian fashion by using a transport equation combined with the incompressible Navier-Stokes equations. The most interesting results can be summarized as follows: (i) the settling velocity is affecting the streamwise vortices at the head of the current with a substantial reduction of their size when the settling velocity is increased; (ii) when the Reynolds number is increased the lobe-and-cleft structures are merging more frequently and earlier in time, suggesting a strong Reynolds number dependence for the spatio-temporal evolution of the head of the current; (iii) the temporal imprint of the lobe-and-cleft structures can be recovered from the deposition map, suggesting that the deposition pattern is defined purely and exclusively by the structures at the front of the current.

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Section: Problem Configuration and Governing Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-fidelity simulations of the lobe-and-cleft structures and the deposition map in particle-driven gravity currents

et al. 2015

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“…The wall-shear stress is often used in theoretical models to predict the possibility of sediment entrainment over loose beds [25,27,19]. The dimensional wall-shear stress in the radial direction is defined as τ w = µ ∂u * R ∂z * z * =0 (10) where, µ represents the dynamic viscosity of the current, u * R is the dimensional horizontal component of velocity in the radial direction, Fig. 11.…”

Section: Wall Shear-stress and Near-wall Dynamicsmentioning

confidence: 99%

“…The first, denoted here as σ , is a result of the gradient of the meso-scale velocity field, it is defined as (12) where ɛ is the strain-rate tensor of the computed meso-scale velocity field. The second type of dissipation is at the micro-scale and is caused by the Stokes flow around the individual particles [10]. Even though our numerical model does not resolve the flow around the individual particles, the latter dissipation may be computed from the local concentration field, viz…”

Section: Energy Budgetmentioning

confidence: 99%

Direct numerical simulation of cylindrical particle-laden gravity currents

2015

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numerical simulation of cylindrical particle-laden gravity currents. Computers and Fluids, Elsevier, 2015, 123, pp.23-31. <10.1016/j.compfluid.2015 b s t r a c tWe present results from direct numerical simulations (DNS) of cylindrical particle-laden gravity currents. We consider the case of a full depth release with monodisperse particles at a dilute concentration where particle-particle interactions may be neglected. The disperse phase is treated as a continuum and a twofluid formulation is adopted. We present results from two simulations at Reynolds numbers of 3450 and 10,000. Our results are in good agreement with previously reported experiments and theoretical models. At early times in the simulations, we observe a set of rolled up vortices that advance at varying speeds. These Kelvin-Helmholtz (K-H) vortex tubes are generated at the surface and exhibit a counter-clockwise rotation. In addition to the K-H vortices, another set of clockwise rotating vortex tubes initiate at the bottom surface and play a major role in the near wall dynamics. These vortex structures have a strong influence on wall shear-stress and deposition pattern. Their relations are explored as well.

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An interactive tool for stratigraphic visualization applied to turbulence-resolved numerical simulations of turbidity currents

Schuch¹,

Vianna²,

Pinho³

et al. 2019

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Two- and three-dimensional Direct Numerical Simulation of particle-laden gravity currents

Cited by 41 publications

References 19 publications

High-fidelity simulations of the lobe-and-cleft structures and the deposition map in particle-driven gravity currents

High-fidelity simulations of the lobe-and-cleft structures and the deposition map in particle-driven gravity currents

Direct numerical simulation of cylindrical particle-laden gravity currents

An interactive tool for stratigraphic visualization applied to turbulence-resolved numerical simulations of turbidity currents

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