Time-dependent non-linear dynamics of polymer solutions in microfluidic contraction flow—a numerical study on the role of elongational viscosity

2013 ◽  
Vol 52 (4) ◽  
pp. 337-354 ◽  
Author(s):  
Sunday C. Omowunmi ◽  
Xue-Feng Yuan
Keyword(s):  
Polymer Solutions ◽  
Numerical Study ◽  
Elongational Viscosity ◽  
Time Dependent ◽  
Contraction Flow ◽  
Linear Dynamics ◽  
Non Linear

Non-linear dynamics of semi-dilute polydisperse polymer solutions in microfluidics: A study of a benchmark flow problem

2011 ◽  
Vol 166 (16) ◽  
pp. 951-963 ◽  
Author(s):  
Zhuo Li ◽  
Xue-Feng Yuan ◽  
Simon J. Haward ◽  
Jeffrey A. Odell ◽  
Stephen Yeates
Keyword(s):  
Polymer Solutions ◽  
Flow Problem ◽  
Linear Dynamics ◽  
Non Linear ◽  
Polydisperse Polymer

Non-linear dynamics of semi-dilute polydisperse polymer solutions in microfluidics: effects of flow geometry

2011 ◽  
Vol 50 (3) ◽  
pp. 277-290 ◽  
Author(s):  
Zhuo Li ◽  
Xue-Feng Yuan ◽  
Simon J. Haward ◽  
Jeffrey A. Odell ◽  
Stephen Yeates
Keyword(s):  
Polymer Solutions ◽  
Linear Dynamics ◽  
Flow Geometry ◽  
Non Linear ◽  
Polydisperse Polymer

Numerical Study on Discharging Characteristics of Pebble Cluster Flow in Pebble Bed

2020 ◽  
Author(s):  
Liang Ge ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
Shengyao Jiang
Keyword(s):  
Numerical Study ◽  
Time Dependent ◽  
Cluster Models ◽  
Movement Behavior ◽  
Pebble Bed ◽  
Included Angle ◽  
Entrance Section ◽  
Flow Features ◽  
Cluster Flow

Abstract To better understand the flow features of pebble cluster in pebble bed, discharging of the pebble cluster were simulated by DEM. The pebble entangled cluster was composed of eight particles connected by rigid bonds and the simulated cluster models are divided into two types: axisymmetric u-particle and distorted z-particle. The simulation starts with the closed discharge outlet and the bonded clusters with different ID are randomly added from the entrance section. The pebbles fall freely and accumulate freely in the pebble bed. The discharge hole opens after all the pebbles being stationary for a period. Then the pebbles are discharged from the pebble bed under gravity. The discharging process is time-dependent bulk-movement behavior. There is not much mixing between layers on the boundary. The vertical end makes the packing loose, but also intensifies the interaction between particles due to entanglement. Consequently, the discharge features of pebble clusters of different included angles were quantified. The results show that the pebble discharging speeds depend on entanglement angle (α of u-particle and η of z-particle) and discharging outlet diameter. A large included angle may play the role of retarding or inhibiting the discharging flowrate. Therefore, the entanglement of particles component also always plays the key role of retarding the discharge.

The competing role of natural gas and oil as fossil fuel and the non-linear dynamics of resource curse in Russia

2021 ◽  
Vol 72 ◽  
pp. 102100
Author(s):  
Jinxuan Yang ◽  
Syed Kumail Abbas Rizvi ◽  
Zhixiong Tan ◽  
Muhammad Umar ◽  
Mansoor Ahmed Koondhar
Keyword(s):  
Natural Gas ◽  
Fossil Fuel ◽  
Resource Curse ◽  
Linear Dynamics ◽  
Non Linear

Role of the autonomic nervous system in generating non-linear dynamics in short-term heart period variability

2006 ◽  
Vol 51 (4) ◽  
pp. 174-177 ◽  
Author(s):  
Alberto Porta ◽  
Stefano Guzzetti ◽  
Ester Borroni ◽  
Raffaello Furlan ◽  
Nicola Montano ◽  
...  
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Heart Period ◽  
Short Term ◽  
Linear Dynamics ◽  
Autonomic Nervous ◽  
Heart Period Variability ◽  
Period Variability ◽  
Non Linear

scholarly journals Numerical Study on Discharging Characteristics of Entangled Cluster of Particles in Particle Bed

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaoli Huang ◽  
Liang Ge ◽  
Nan Gui ◽  
X. T. Yang ◽  
J. Y. Tu ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Flow Rate ◽  
Numerical Study ◽  
Discrete Element ◽  
Time Dependent ◽  
Movement Behavior ◽  
Particle Cluster ◽  
Flow Features ◽  
Particle Bed

To better understand the flow features of the particle cluster in a particle bed, discharging of the particle entangled cluster is simulated by the discrete element method (DEM). The particle entangled cluster is composed of eight particles connected by rigid bonds, and the simulated entangled cluster models are divided into two types: axisymmetric u-particles and distorted z-particles. The simulation starts with the closed discharge outlet, and the bonded clusters with different IDs are randomly added from the entrance section. The particles fall freely and accumulate freely in the particle bed. The discharge hole opens after all the particles are stationary for a period. Then, the particles are discharged from the particle bed under gravity. The discharging process has time-dependent bulk-movement behavior. There is not much mixing between layers on the boundary. The vertical end not only makes the packing loose but also intensifies the interaction between particles due to entanglement. Consequently, the discharge features of particle entangled clusters of different included angles were quantified. The results show that the particle discharging speeds depend on the entanglement angle (α of u-particles and η of z-particles) and discharging outlet diameter. A large included angle may play the role of retarding or inhibiting the discharging flow rate. Therefore, the entanglement of particle components also always plays the key role of retarding the discharge.

Steady free convection in a porous medium heated from below

1967 ◽  
Vol 27 (1) ◽  
pp. 29-48 ◽  
Author(s):  
J. W. Elder
Keyword(s):  
Porous Medium ◽  
Free Convection ◽  
Numerical Scheme ◽  
Numerical Study ◽  
Critical Rayleigh Number ◽  
Linear Process ◽  
Wave Number ◽  
End Effects ◽  
Non Linear

This is an experimental and numerical study of steady free convection in a porous medium, a system dominated by a single non-linear process, the advection of heat. The paper presents results on three topics: (1) a system uniformly heated from below, for which the flow is cellular, as in the analogous Bénard-Rayleigh flows, (ii) the role of end-effects, and (iii) the role of mass discharge. Measurements of heat transfer are used to establish further the validity of the numerical scheme proposed by the author (1966a), while the other flows allow a more extensive study of the numerical scheme under various boundary conditions. The results are very satisfactory even though only moderately non-linear problems can be treated at present.The main new results are as follows. For the Rayleigh-type flow, above a critical Rayleigh number of about 40, the heat transferred across the layer is proportional to the square of the temperature difference across the layer and is independent of the thermal conductivity of the medium or the depth of the layer. This result is modified when the boundary-layer thickness is comparable to the grain size of the medium. The investigation of end-effects reveals variations in horizontal wave-number and a pronounced hysteresis and suggests an alternative explanation of some observations by Malkus (1954).

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