Microstructure-informed probability-driven point-particle model for hydrodynamic forces and torques in particle-laden flows

2020 ◽  
Vol 900 ◽  
Author(s):  
Arman Seyed-Ahmadi ◽  
Anthony Wachs
Keyword(s):  
Hydrodynamic Forces ◽  
Point Particle ◽  
Particle Model ◽  
Particle Laden Flows ◽  
Image Position

Abstract

Monte Carlo Schemes for Radiative Transfer in Media Represented by Particle Fields

2005 ◽  
Author(s):  
Anquan Wang ◽  
Michael F. Modest
Keyword(s):  
Monte Carlo ◽  
Ray Tracing ◽  
Radiative Heat ◽  
Solid Angle ◽  
Scalar Fields ◽  
Point Particle ◽  
Particle Model ◽  
Test Problems ◽  
Combustion Modeling ◽  
Radiation Properties

Monte Carlo ray-tracing schemes are developed for the evaluation of radiative heat transfer for problems, in which the participating medium is represented by discrete point-masses, such as the flow field and scalar fields in PDF Monte Carlo methods frequently used in combustion modeling. Photon ray tracing in such cases requires that an optical thickness is assigned to each of the point-masses. Two approaches are discussed, the Point Particle Model (PPM), in which the shape of particle is not specified, and the Spherical Particle Model (SPM) in which particles are assumed to be spheres with constant radiation properties. Another issue for ray tracing in particle fields is the influence region of a ray. Two ways of modeling a ray are proposed. In the first, each ray is treated as a standard volume-less line. In the other approach, the ray is assigned a small solid angle, and is thus treated as a cone with a decaying influence function away from its center line. Based on these models, three different interaction schemes between rays and particles are proposed, i.e., Line-SPM, Cone-PPM and Cone-SPM methods, and are compared employing several test problems.

On the Predictive Capability of DNS-DEM Applied to Suspended Sediment-Turbulence Interactions

2017 ◽  
Author(s):  
Pedram Pakseresht ◽  
Sourabh V. Apte ◽  
Justin R. Finn
Keyword(s):  
Point Particle ◽  
Particle Model ◽  
Wall Region ◽  
Dynamical Interaction ◽  
Kolmogorov Length Scale ◽  
Large Particles ◽  
Wall Collision ◽  
Kolmogorov Scale ◽  
Particle Approach ◽  
Near Wall

DNS coupled with a Point-Particle based model (PP) is used to study and predict particle-turbulence interactions in an open channel flow at Reynolds number of 811 (based on the friction velocity) corresponding to the experimental observations of [Righetti & Romano, JFM 2004]. Large particles of diameter 200 microns (8.1 in wall units) with average volume loading on the order of 0.001 are simulated using four-way coupling with closure models for drag, added mass, lift, pressure, and inter-particle/particle-wall collision forces. The point-particle model is able to accurately capture the effect of particles on the fluid flow in the outer layer where particles are under resolved. However, the dynamical interaction of particle-turbulence is under predicted in the near wall region where particles size are much larger than Kolmogorov scale and grid resolution in wall-normal direction, but smaller in both stream and span wise directions. It is conjectured that due to the large size particles compared to the Kolmogorov length scale near the bed, the effect of disturbances and deflections in the flow due to presence of such large particles is not captured using Lagrangian Point-Particle approach. For this configuration, the point-particle model is not appropriate in the near wall region and a hybrid resolved particle approach may be necessary.

A point-particle model universe

1982 ◽  
Vol 14 (6) ◽  
pp. 591-608 ◽  
Author(s):  
R. P. A. C. Newman ◽  
G. C. McVittie
Keyword(s):  
Point Particle ◽  
Particle Model ◽  
Model Universe

Photon Monte Carlo Simulation for Radiative Transfer in Gaseous Media Represented by Discrete Particle Fields

2006 ◽  
Vol 128 (10) ◽  
pp. 1041-1049 ◽  
Author(s):  
Anquan Wang ◽  
Michael F. Modest
Keyword(s):  
Monte Carlo ◽  
Ray Tracing ◽  
Radiative Heat ◽  
Scalar Fields ◽  
Point Particle ◽  
Particle Model ◽  
Test Problems ◽  
Combustion Modeling ◽  
Radiation Properties ◽  
Gaseous Media

Monte Carlo ray-tracing schemes have been developed for the evaluation of radiative heat transfer for problems, in which the participating medium is represented by discrete point masses, such as the flow field and scalar fields in PDF Monte Carlo methods frequently used in combustion modeling. Photon ray tracing in such cases requires that an optical thickness is assigned to each of the point masses. Two approaches are discussed, the point particle model (PPM), in which the shape of particle is not specified, and the spherical particle model (SPM) in which particles are assumed to be spheres with specified radiation properties across their volumes. Another issue for ray tracing in particle fields is the influence region of a ray. Two ways of modeling a ray are proposed. In the first, each ray is treated as a standard volume-less line. In the other approach, the ray is assigned a small solid angle, and is thus treated as a cone with a decaying influence function away from its centerline. Based on these models, three different interaction schemes between rays and particles are proposed, i.e., line-SPM, cone-PPM and cone-SPM methods, and are compared employing several test problems.

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