scholarly journals Effects of particle-fluid density ratio on the interactions between the turbulent channel flow and finite-size particles

2017 ◽  
Vol 96 (3) ◽  
Author(s):  
Zhaosheng Yu ◽  
Zhaowu Lin ◽  
Xueming Shao ◽  
Lian-Ping Wang
Keyword(s):  
Channel Flow ◽  
Density Ratio ◽  
Finite Size ◽  
Turbulent Channel Flow ◽  
Fluid Density

A direct numerical investigation of two-way interactions in a particle-laden turbulent channel flow

2019 ◽  
Vol 875 ◽  
pp. 1096-1144 ◽  
Author(s):  
Cheng Peng ◽  
Orlando M. Ayala ◽  
Lian-Ping Wang
Keyword(s):  
Channel Flow ◽  
Finite Size ◽  
Turbulent Channel Flow ◽  
Spherical Particles ◽  
Homogeneous Distribution ◽  
Particle Sizes ◽  
Small Particles ◽  
Particle Rotation ◽  
Turbulence Modulation ◽  
Budget Analysis

Understanding the two-way interactions between finite-size solid particles and a wall-bounded turbulent flow is crucial in a variety of natural and engineering applications. Previous experimental measurements and particle-resolved direct numerical simulations revealed some interesting phenomena related to particle distribution and turbulence modulation, but their in-depth analyses are largely missing. In this study, turbulent channel flows laden with neutrally buoyant finite-size spherical particles are simulated using the lattice Boltzmann method. Two particle sizes are considered, with diameters equal to 14.45 and 28.9 wall units. To understand the roles played by the particle rotation, two additional simulations with the same particle sizes but no particle rotation are also presented for comparison. Particles of both sizes are found to form clusters. Under the Stokes lubrication corrections, small particles are found to have a stronger preference to form clusters, and their clusters orientate more in the streamwise direction. As a result, small particles reduce the mean flow velocity less than large particles. Particles are also found to result in a more homogeneous distribution of turbulent kinetic energy (TKE) in the wall-normal direction, as well as a more isotropic distribution of TKE among different spatial directions. To understand these turbulence modulation phenomena, we analyse in detail the total and component-wise volume-averaged budget equations of TKE with the simulation data. This budget analysis reveals several mechanisms through which the particles modulate local and global TKE in the particle-laden turbulent channel flow.

scholarly journals The effect of particle density in turbulent channel flow laden with finite size particles in semi-dilute conditions

2016 ◽  
Vol 28 (3) ◽  
pp. 033301 ◽  
Author(s):  
W. Fornari ◽  
A. Formenti ◽  
F. Picano ◽  
L. Brandt
Keyword(s):  
Channel Flow ◽  
Particle Density ◽  
Finite Size ◽  
Turbulent Channel Flow

scholarly journals Flow Modulation by Finite-Size Neutrally Buoyant Particles in a Turbulent Channel Flow

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Lian-Ping Wang ◽  
Cheng Peng ◽  
Zhaoli Guo ◽  
Zhaosheng Yu
Keyword(s):  
Particle Size ◽  
Solid Particle ◽  
Channel Flow ◽  
Volume Fraction ◽  
Finite Size ◽  
Turbulent Channel Flow ◽  
Solid Particles ◽  
Momentum Exchange ◽  
Flow Modulation ◽  
Neutrally Buoyant

A fully mesoscopic, multiple-relaxation-time (MRT) lattice Boltzmann method (LBM) is developed to perform particle-resolved direct numerical simulation (DNS) of wall-bounded turbulent particle-laden flows. The fluid–solid particle interfaces are treated as sharp interfaces with no-slip and no-penetration conditions. The force and torque acting on a solid particle are computed by a local Galilean-invariant momentum exchange method. The first objective of the paper is to demonstrate that the approach yields accurate results for both single-phase and particle-laden turbulent channel flows, by comparing the LBM results to the published benchmark results and a full-macroscopic finite-difference direct-forcing (FDDF) approach. The second objective is to study turbulence modulations by finite-size solid particles in a turbulent channel flow and to demonstrate the effects of particle size. Neutrally buoyant particles with diameters 10% and 5% the channel width and a volume fraction of about 7% are considered. We found that the mean flow speed was reduced due to the presence of the solid particles, but the local phase-averaged flow dissipation was increased. The effects of finite particle size are reflected in the level and location of flow modulation, as well as in the volume fraction distribution and particle slip velocity near the wall.

Turbulence modulation by finite-size heavy particles in a downward turbulent channel flow

2021 ◽  
Vol 33 (6) ◽  
pp. 063321
Author(s):  
Yan Xia ◽  
Zhaowu Lin ◽  
Dingyi Pan ◽  
Zhaosheng Yu
Keyword(s):  
Channel Flow ◽  
Finite Size ◽  
Turbulent Channel Flow ◽  
Heavy Particles ◽  
Turbulence Modulation
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