scholarly journals Comparison of Collision Dynamics of Non-Spherical Particles between the Hard-Particle Model and Soft-Particle Model

2017 ◽  
Vol 07 (04) ◽  
pp. 97-102
Author(s):  
达岭 吴
Keyword(s):  
Spherical Particles ◽  
Particle Model ◽  
Soft Particle ◽  
Hard Particle ◽  
Collision Dynamics

An accurate method to include lubrication forces in numerical simulations of dense Stokesian suspensions

2015 ◽  
Vol 769 ◽  
pp. 369-386 ◽  
Author(s):  
A. Lefebvre-Lepot ◽  
B. Merlet ◽  
T. N. Nguyen
Keyword(s):  
Short Range ◽  
Degrees Of Freedom ◽  
Computational Cost ◽  
Parameter Tuning ◽  
Accurate Method ◽  
Spherical Particles ◽  
Particle Model ◽  
Stokesian Dynamics ◽  
New Feature ◽  
The Many

We address the problem of computing the hydrodynamic forces and torques among $N$ solid spherical particles moving with given rotational and translational velocities in Stokes flow. We consider the original fluid–particle model without introducing new hypotheses or models. Our method includes the singular lubrication interactions which may occur when some particles come close to one another. The main new feature is that short-range interactions are propagated to the whole flow, including accurately the many-body lubrication interactions. The method builds on a pre-existing fluid solver and is flexible with respect to the choice of this solver. The error is the error generated by the fluid solver when computing non-singular flows (i.e. with negligible short-range interactions). Therefore, only a small number of degrees of freedom are required and we obtain very accurate simulations within a reasonable computational cost. Our method is closely related to a method proposed by Sangani & Mo (Phys. Fluids, vol. 6, 1994, pp. 1653–1662) but, in contrast with the latter, it does not require parameter tuning. We compare our method with the Stokesian dynamics of Durlofsky et al. (J. Fluid Mech., vol. 180, 1987, pp. 21–49) and show the higher accuracy of the former (both by analysis and by numerical experiments).

scholarly journals Experimental and Computational Studies of Gravity-Driven Dense Granular Flows

2015 ◽  
Author(s):  
Yesaswi N. Chilamkurti ◽  
Richard D. Gould
Keyword(s):  
Three Dimensional ◽  
Granular Flows ◽  
Packing Fraction ◽  
Velocity Shear ◽  
Spherical Particles ◽  
Tube Length ◽  
Soft Particle ◽  
Mean Velocity ◽  
Gravity Driven ◽  
Dense Granular Flows

The current paper focusses on the characterization of gravity-driven dry granular flows in cylindrical tubes. With a motive of using dense particulate media as heat transfer fluids (HTF), the study was primarily focused to address the characteristics of flow regimes with a packing fraction of ∼60%. Experiments were conducted to understand the effects of different flow parameters, including: tube radius, tube inclination, tube length and exit diameter. These studies were conducted on two types of spherical particles — glass and ceramic — with mean diameters of 150 μm and 300 μm respectively. The experimental data was correlated with the semi-empirical equation based on Beverloo’s law. In addition, the same flow configuration was studied through three-dimensional computer simulations by implementing the Discrete Element Method for the Lagrangian modelling of particles. A soft-particle formulation was used with Hertz-Mindilin contact models to resolve the interaction forces between particles. The simulation results were used to examine the velocity, shear rate and packing fraction profiles to study the detailed flow dynamics. Curve-fits were developed for the mean velocity profiles which could be used in developing hydrodynamic analogies for granular flows. The current work thus identifies the basic features of gravity driven dense granular flows that could form a basis for defining their rheology.

Sorption Kinetics of Non-Ionic Organic Pollutants Onto Suspended Sediments

1991 ◽  
Vol 23 (1-3) ◽  
pp. 447-454 ◽  
Author(s):  
H. M. Liljestrand ◽  
Y. D. Lee
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Experimental Studies ◽  
Size Fraction ◽  
Organic Matter Content ◽  
Suspended Sediments ◽  
Spherical Particles ◽  
Particle Model ◽  
Desorption Kinetics ◽  
Kinetics Of

The results of controlled batch experimental studies of the adsorption and desorption kinetics of dichlorobenzene to 1) size fractionated, washed sediments, 2) aggregate, washed sediment, 3) dissolved/colloidal sediment materials, and 4) bulk sediments,are used to determine the effect of inhomogeneous mixtures on the overall sorption rates. The size-segregated sediments are modeled as spherical particles with a porous outer shell of organic matter for sorption and an inert, inorganic core. The characteristic times of intraparticle diffusive transport are found to vary with particle size by about two orders of magnitude. The distribution of natural organic matter content with particle size results in sorption rates which differ greatly from that predicted by the monodisperse, homogeneous particle model. Coupled, reversible reactions between the solute and each solid size fraction are presented as a conceptual model for the interpretation of the empirical results of batch experiments.

scholarly journals Soft particle model for block copolymers

2007 ◽  
Vol 127 (13) ◽  
pp. 134905 ◽  
Author(s):  
F. Eurich ◽  
A. Karatchentsev ◽  
J. Baschnagel ◽  
W. Dieterich ◽  
P. Maass
Keyword(s):  
Block Copolymers ◽  
Particle Model ◽  
Soft Particle
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