Interface-resolved simulations of small inertial particles in turbulent channel flow – CORRIGENDUM

Costa, Pedro; Brandt, Luca; Picano, Francesco

doi:10.1017/jfm.2020.199

Cited by 5 publications

(20 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These studies mostly focused on inertial particles with a size much larger than Kolmogorov length scale, and detailed mechanisms of turbulence modulation were concluded using various statistical methods. Recently, by comparing the results between particle-resolved simulation and one-way coupled point-particle simulation, Costa et al (2020aCosta et al ( , 2020b found that when the modified Saffman lift force is included, the statistical results between two simulations are very similar, thus supporting the validity of the pointparticle method.…”

Section: Introductionmentioning

confidence: 94%

“…( 2), the terms on the right hand side are drag force, buoyancy force, lift force, pressure gradient force, and added mass force, respectively. Their contributions to the total force when compared with the drag force are discussed in Armenio and Fiorotto (2001) and Mortimer et al (2019).T h el i f tf o r c e [ Costa et al, (2020a[ Costa et al, ( ,2020b], the pressure gradient force, and the added mass force (Mortimer et al,2 0 1 9 ) are included because of their gradually increasing effect upon approaching the wall. Costa et al (2020aCosta et al ( , 2020b also found that the point-particle method with the Saffman lift model included can have similar statistical results with those from the particle-resolved method.…”

Section: Articlementioning

confidence: 99%

“…Their contributions to the total force when compared with the drag force are discussed in Armenio and Fiorotto (2001) and Mortimer et al (2019).T h el i f tf o r c e [ Costa et al, (2020a[ Costa et al, ( ,2020b], the pressure gradient force, and the added mass force (Mortimer et al,2 0 1 9 ) are included because of their gradually increasing effect upon approaching the wall. Costa et al (2020aCosta et al ( , 2020b also found that the point-particle method with the Saffman lift model included can have similar statistical results with those from the particle-resolved method. The basset force is neglected as its calculation is very time consuming, and when the density ratio larger than 100, the leading force is the drag force and the buoyancy force (Armenio andFiorotto, 2001 andMortimer et al, 2019).…”

Section: Articlementioning

confidence: 99%

See 2 more Smart Citations

Direct numerical simulation of bidisperse inertial particles settling in turbulent channel flow

2021

View full text Add to dashboard Cite

The behavior of settling velocity and clustering of bidisperse inertial particles in a turbulent channel flow is investigated through direct numerical simulation. The particle-laden planar channel flow has a friction Reynolds number at Re s ¼ 180. Eulerian-Lagrangian method is used to study the dynamic properties of bidisperse and monodisperse inertial particles with 16 different simulation sets, which are distinguished by Stokes numbers ranging from St þ ¼ 1.31 to 52.58 and particle number ratio from 1:1 to 1:8. Momentum exchange between fluid and particle phases is considered in the simulation as the chosen initial volume fraction at 5 Â 10 À5 is in the two-way coupling regime. The gravity is set at the direction normal to both the wall normal direction and the streamwise direction. We observe that in the bidisperse cases the turbophoresis effect of inertial particles with the smaller diameter is significant even though it is very weak in the corresponding monodisperse cases. We use radial distribution function (RDF) to investigate the degree of clustering and turbophoresis. The results indicate that RDF is larger in the bidisperse cases for both large and small particles and it is greatly affected by the bulk particle number ratio and the Stokes number ratio. Unlike clustering, the terminal settling velocities of inertial particles in the bidisperse cases are affected by the final volume fraction at the dynamic equilibrium state. When their final volume fractions are lower than those in the corresponding monodisperse cases, the settling velocity of either particle becomes reduced from the monodisperse value. We also investigate the relationship between settling velocity and vortex strength. The results show that the preferential sweeping mechanism is strengthened with Stokes number decreasing and the mechanism can be quantified by the slope of the curve of settling velocity variation with vortex strength.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Articlementioning

confidence: 99%

Section: Articlementioning

confidence: 99%

See 1 more Smart Citation

Direct numerical simulation of bidisperse inertial particles settling in turbulent channel flow

2021

View full text Add to dashboard Cite

show abstract

“…Among the catalogue of expressions for shear-induced lift force, Saffman-Mei was chosen as its ability to capture near-wall statistics is corroborated by state-of-the-art particle-resolved DNS (Costa, Brandt & Picano 2020b). As such, equations for particle motion are (ODEs) associated with particle motion are integrated in time through an implicit Euler scheme.…”

Section: Computational Set-upmentioning

confidence: 99%

“…Liu & Agarwal 1974) and the analytical work presented in § 1.1. Sets 3 and 4, are similar to Sets 1 and 2, respectively, except that the Saffman-Mei lift force F l is included in the particle dynamics, which was found to yield better agreement with fully resolved particle simulations (Costa et al 2020b). The purpose of these four sets is to test the robustness of particle-wall interaction and force treatments on particle dynamics.…”

Section: Computational Set-upmentioning

confidence: 99%

Particle transport in a turbulent pipe flow: direct numerical simulations, phenomenological modelling and physical mechanisms

Zahtila

Chan²,

Ooi³

et al. 2023

J. Fluid Mech.

View full text Add to dashboard Cite

In particle-laden turbulent wall flows, transport of particles towards solid walls is phenomenologically thought to be governed by the wall-normal turbulence intensity supporting the underlying particle–eddy interactions that are usually modelled by a combination of turbophoresis and turbulent diffusion. We estimate the turbophoretic and turbulent diffusive coefficients as a function of wall-normal coordinate directly from a generated direct numerical simulation (DNS) database of low volume fraction point particles in a turbulent pipe flow. These coefficients are then used in an advection–diffusion equation to estimate the particle concentration as a function of wall-normal distance and time, with favourable comparison against DNS for smaller Stokes number ( $St^+$ ) particles suggesting a limitation of the common gradient diffusion hypothesis for larger $St^+$ particles. Using DNS we explore the non-trivial effects of $St^+$ , pipe wall condition (particle absorbing or elastic) as well as the influence of drag and lift force on the velocity and particle statistics giving rise to different particle concentrations. We then appraise various Eulerian-based models of turbophoretic and turbulent diffusive coefficients and, finally, use physical insights from Lagrangian correlation times, conditional quadrant analysis and flow topology to shed further light on the particle transport as a function of various parameters and the limits of gradient diffusion hypothesis.

show abstract

On the shear-induced lift in two-way coupled turbulent channel flow laden with heavy particles

Ruan,

Xiao

2024

J. Fluid Mech.

View full text Add to dashboard Cite

The importance of shear-induced lift, i.e. Saffman lift, is investigated in two-way coupling point-particle direct numerical simulation of turbulent channel flow laden with heavy particles. A new criterion is established for the critical particle diameter normalized by wall viscous length, and the effect of Saffman lift on particle motion can be neglected when the particle diameter is smaller than the critical value. The new criterion agrees well with the numerical results. We further study the influence of Saffman lift on particle motion and turbulence modulation. The results suggest that the Saffman lift will increase near-wall particle velocity and reduce particle accumulation therein. By integrating the particle motion equation, it is demonstrated that the mean particle streamwise velocity is dependent on the particle wall-normal velocity. This theoretically explains why the presence of a wall-normal force alters the streamwise velocity of particles. A theoretical profile of mean particle streamwise velocity at different Stokes numbers is then obtained by introducing the diffusive gradient hypothesis and Prandtl mixing length model. In addition, the present results reveal that the Saffman lift tends to augment the level of turbulence attenuation. The spectral analysis shows that the Saffman lift reduces the turbulent energy of small scales in the buffer region and large structures in the logarithmic region. When the Saffman lift is absent, near-wall particle streaks can be observed in the buffer region, which tend to separate fluid streaks. By contrast, the Saffman lift tends to prevent the formation of near-wall particle streaks.

show abstract

Interface-resolved simulations of small inertial particles in turbulent channel flow – CORRIGENDUM

Abstract: Equation (2.10) in Costa, Brandt & Picano (2020) for the lift force model used in the point-particle direct numerical simulations (DNS), and which is derived from the classical lift force of Saffman (1965),

Cited by 5 publications

References 4 publications

Direct numerical simulation of bidisperse inertial particles settling in turbulent channel flow

Direct numerical simulation of bidisperse inertial particles settling in turbulent channel flow

Particle transport in a turbulent pipe flow: direct numerical simulations, phenomenological modelling and physical mechanisms

On the shear-induced lift in two-way coupled turbulent channel flow laden with heavy particles

Contact Info

Product

Resources

About