scholarly journals Unconventional rheological properties in systems of deformable particles

Soft Matter ◽  
2021 ◽  
Author(s):  
Anshuman Pasupalak ◽  
Shawn KHUHAN SAMIDURAI ◽  
Yan-Wei Li ◽  
Yuanjian Zheng ◽  
Ran Ni ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Rheological Properties ◽  
Large Strains ◽  
Deformable Particles

We demonstrate the existence of unconventional rheological and memory properties in systems of soft-deformable particles whose energy depends on their shape, via numerical simulations. At large strains, these systems experience...

Particle Dispersion Simulator for Gel Printer

2014 ◽  
Vol 783-786 ◽  
pp. 2333-2338
Author(s):  
Masato Makino ◽  
M. Hasnat Kabir ◽  
Jin Gong ◽  
Hidemitsu Furukawa
Keyword(s):  
Lattice Boltzmann Method ◽  
Rheological Properties ◽  
Lattice Boltzmann ◽  
Particle Dispersion ◽  
Deformable Particles ◽  
Boltzmann Method ◽  
Dynamics Of Particles

We are developing food printer to design arbitrary shaped foods. The ink for the food printer, injected from nozzle to make foods, is the dispersion of rigid and deformable particles. Simulation for rheological properties and interaction among particles and walls could be one of the important tools to develop the ink for the food printer. We introduce our simulators to investigate the dynamics of particles dispersion. The particles are expressed as Lagrange mesh immersed in fluid. The fluid is solved by Lattice Boltzmann method. The viscosity of the dispersion of the rigid and the deformable particles is shown in this study.

scholarly journals Measuring Rheological Properties of Cement Pastes: Most common Techniques, Procedures and Challenges

2017 ◽  
Vol 2 ◽  
pp. 129-135 ◽  
Author(s):  
Dimitri Feys ◽  
Rolands Cepuritis ◽  
Stefan Jacobsen ◽  
Karel Lesage ◽  
Egor Secrieru ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Rheological Properties ◽  
Cement Paste ◽  
Testing Procedure ◽  
Phenomenological Description ◽  
Flow Properties ◽  
Cement Pastes ◽  
Fundamental Investigation

The science of rheology is increasingly used to describe the properties of fresh cement paste. Compared to standard workability tests, rheological properties allow for more fundamental investigation, more precise phenomenological description of flow properties and serve as input for numerical simulations. Standard commercially available rheometers are typically used to perform those measurements. However, the results of the measurement depend on the geometry, testing procedure and a number of potential artefacts which may occur. This technical letter describes the most common techniques and procedures used to assess the rheological properties of cement paste, as well as challenges during measurements and actions to counter these challenges.

scholarly journals Shear banding from lattice kinetic models with competing interactions

2011 ◽  
Vol 369 (1945) ◽  
pp. 2439-2447 ◽  
Author(s):  
Roberto Benzi ◽  
Mauro Sbragaglia ◽  
Massimo Bernaschi ◽  
Sauro Succi
Keyword(s):  
Kinetic Model ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Kinetic Models ◽  
Shear Banding ◽  
Computational Investigation ◽  
Confined Geometries ◽  
Competing Interactions ◽  
Glassy Materials ◽  
Soft Glassy Materials

We present numerical simulations based on a Boltzmann kinetic model with competing interactions, aimed at characterizing the rheological properties of soft-glassy materials. The lattice kinetic model is shown to reproduce typical signatures of driven soft-glassy flows in confined geometries, such as Herschel–Bulkley rheology, shear banding and hysteresis. This lends further credit to the present lattice kinetic model as a valuable tool for the theoretical/computational investigation of the rheology of driven soft-glassy materials under confinement.

scholarly journals Numerical Modeling of p-v-T Rheological Equation Coefficients for Polypropylene with Variable Chalk Content

2019 ◽  
Vol 9 (1) ◽  
pp. 668-673
Author(s):  
Tomasz Jachowicz ◽  
Ivan Gajdos ◽  
Volodymyr Krasinskiy
Keyword(s):  
Mathematical Model ◽  
Numerical Modeling ◽  
Injection Molding ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Specific Volume ◽  
Mineral Filler ◽  
Rheological Equation ◽  
Computer Methods ◽  
Temperature And Pressure

AbstractThe paper reports the experimental results of a study investigating the effect of different contents of a mineral filler on the rheological properties, p-v-T, of polypropylene. Using the pvT100 apparatus, we measured specific volume under isobaric cooling at different pressures for pure polypropylene and chalk-filled polypropylene (10 wt%, 20 wt% and 30 wt%). Next, we employed computer methods to determine the coefficients of a mathematical model describing the variations in specific volume in a function of temperature and pressure. The model was used in the numerical simulations of injection molding and shrinkage processes.

scholarly journals Impact of a Random Sequence of Debris Flows on Torrential Fan Formation

Geosciences ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 64 ◽  
Author(s):  
Nejc Bezak ◽  
Jošt Sodnik ◽  
Matjaž Mikoš
Keyword(s):  
Debris Flow ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Debris Flows ◽  
Random Sequence ◽  
Rheological Parameters ◽  
Model Parameters ◽  
Maximum Height ◽  
Wide Range ◽  
The Impact

Debris flows with different magnitudes can have a large impact on debris fan characteristics such as height or slope. Moreover, knowledge about the impact of random sequences of debris flows of different magnitudes on debris fan properties is sparse in the literature and can be improved using numerical simulations of debris fan formation. Therefore, in this paper we present the results of numerical simulations wherein we investigated the impact of a random sequence of debris flows on torrential fan formation, where the total volume of transported debris was kept constant, but different rheological properties were used. Overall, 62 debris flow events with different magnitudes from 100 m3 to 20,000 m3 were selected, and the total volume was approximately 225,000 m3. The sequence of these debris flows was randomly generated, and selected debris fan characteristics after the 62 events were compared. For modeling purposes, we applied the Rapid Mass Movement Simulations (RAMMS) software and its debris flow module (RAMMS-DF). The modeling was carried out using (a) real fan topography from an alpine environment (i.e., an actual debris fan in north-west (NW) Slovenia formed by the Suhelj torrent) and (b) an artificial surface with a constant slope. Several RAMMS model parameters were tested. The simulation results confirm that the random sequence of debris flow events has only some minor effects on the fan formation (e.g., slope, maximum height), even when changing debris flow rheological properties in a wide range. After the 62 events, independent of the selected sequence of debris flows, the final fan characteristics were not significantly different from each other. Mann–Whitney (MW) tests and t-tests were used for this purpose, and the selected significance level was 0.05. Moreover, this conclusion applies for artificial and real terrain and for a wide range of tested RAMMS model rheological parameters. Further testing of the RAMMS-DF model in real situations is proposed in order to better understand its applicability and limitations under real conditions for debris flow hazard assessment or the planning of mitigation measures.

scholarly journals Squirming through shear-thinning fluids

2015 ◽  
Vol 784 ◽  
Author(s):  
Charu Datt ◽  
Lailai Zhu ◽  
Gwynn J. Elfring ◽  
On Shun Pak
Keyword(s):  
Asymptotic Analysis ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Reynolds Numbers ◽  
Shear Thinning ◽  
Fundamental Question ◽  
Low Reynolds Numbers ◽  
Shear Thinning Fluids ◽  
Micro Organisms ◽  
Shear Thinning Fluid

Many micro-organisms find themselves immersed in fluids displaying non-Newtonian rheological properties such as viscoelasticity and shear-thinning viscosity. The effects of viscoelasticity on swimming at low Reynolds numbers have already received considerable attention, but much less is known about swimming in shear-thinning fluids. A general understanding of the fundamental question of how shear-thinning rheology influences swimming still remains elusive. To probe this question further, we study a spherical squirmer in a shear-thinning fluid using a combination of asymptotic analysis and numerical simulations. Shear-thinning rheology is found to affect a squirming swimmer in non-trivial and surprising ways; we predict and show instances of both faster and slower swimming depending on the surface actuation of the squirmer. We also illustrate that while a drag and thrust decomposition can provide insights into swimming in Newtonian fluids, extending this intuition to problems in complex media can prove problematic.

scholarly journals Dynamic rheological properties of mixed carrageenan gels under large strains

2017 ◽  
Vol 31 (2) ◽  
pp. 35-39 ◽  
Author(s):  
Stephen L. Flores ◽  
Faith Bernadette A. Descallar ◽  
Shingo Matsukawa ◽  
Rommel G. Bacabac
Keyword(s):  
Rheological Properties ◽  
Large Strains ◽  
Dynamic Rheological Properties

NUMERICAL ANALYSIS OF OPERATING PARAMETERS OF HYDRODYNAMIC THRUST BEARINGS LUBRICATED WITH MAGNETIC FLUID

Tribologia ◽  
2020 ◽  
Vol 291 (3) ◽  
pp. 43-51
Author(s):  
Marcin Szczęch ◽  
Wojciech Horak ◽  
Yuliia Tarasevych
Keyword(s):  
Comparative Analysis ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Operating Parameters ◽  
Thrust Bearings ◽  
Bearing Load ◽  
Functional Features ◽  
Thrust Pad ◽  
Load Conditions

The paper presents the results of numerical simulations (CFD) of hydrodynamic thrust slide bearings lubricated with magnetorheological (MR) fluid. The analyses were carried out to evaluate the influence of the rheological properties of the lubricant, as well as the geometry of the bearing's thrust pad surface. Bearing load conditions were considered on the key functional features of the system, i.e. axial force and torque. The paper presents a comparative analysis of various geometries of thrust bearings and points out possible functional features of hydrodynamic thrust bearings lubricated with fluids with controlled rheological properties.

Rheological Properties of Emulsions Immersed in Electric Fields

2007 ◽  
Author(s):  
Arturo Ferna´ndez
Keyword(s):  
Viscous Fluid ◽  
Electric Field ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Normal Stress ◽  
Electric Fields ◽  
Fluid Motion ◽  
Fluid Shear ◽  
Normal Stress Differences ◽  
Viscous Fluid Motion

The results of fully three-dimensional direct numerical simulations of the effects of electric fields on emulsions of drops will be displayed. The examination of the rheological properties of these systems is performed by imposing a simple-shear flow between two plates where the drops are immersed. An electric potential difference is applied perpendicular to the plates. The resulting electric field leads to two effects: a polarization of the drops and a viscous fluid motion on the interface between the drops and the suspending fluid. The direction and intensity of the viscous fluid motion depends on the electrical properties of the fluids. Drops more conductive than the suspending fluid exhibit a viscous fluid motion from the equator to the poles, whereas drops less conductive than the suspending fluid exhibit a viscous fluid motion from the poles to the equator. The numerical simulations show that the response of the emulsions is governed by the competition between the electric attraction and the fluid shear. The former leads to the aggregation of the drops in chains parallel to the electric field, while the latter tries to break-up the aggregated chains. The results are presented as a function of the Mason number and the electric capillary number, Mn and Ce. These non-dimensional numbers quantify the strength of the electric forces versus the fluid shear and the capillary forces, respectively. The significance of the electrical field on the viscosity and the normal stress differences will be discussed: At low Mason numbers, Mn<0.1, the application of the electric field results in the aggregation of the drops. This aggregation leads to an increase in the effective viscosity of the system and to an increase in the stresses, which result in higher normal stress differences than in hydrodynamic emulsions. At high Mason numbers, Mn>1.0, the fluid shear breaks up the aggregated structures and the properties are similar to hydrodynamic emulsions. At 0.1<Mn<1.0 the properties of the emulsions exhibit an intermediate behavior.

Influence of the Nozzle Shape on the Breakup Behavior of Continuous Ink Jets

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Maxime Rosello ◽  
Guillaume Maîtrejean ◽  
Denis C. D. Roux ◽  
Pascal Jay ◽  
Bruno Barbet ◽  
...  
Keyword(s):  
Surface Tension ◽  
Numerical Simulations ◽  
Rheological Properties ◽  
Simple Approach ◽  
Nozzle Outlet ◽  
Jet Breakup ◽  
Wide Range ◽  
Ink Jet ◽  
Nozzle Shape ◽  
Newtonian Behavior

In this work, the influence of nozzle shape on microfluidic ink jet breakup is investigated. First, an industrial ink used in continuous inkjet (CIJ) printing devices is selected. Ink rheological properties are measured to ensure an apparent Newtonian behavior and a constant surface tension. Then, breakup lengths and shapes are observed on a wide range of disturbance amplitude for four different nozzles. Later on, ink breakup behaviors are compared to the linear theory. Finally, these results are discussed using numerical simulations to highlight the influence of the velocity profiles at the nozzle outlet. Using such computations, a simple approach is derived to accurately predict the breakup length for industrial CIJ nozzles.

Sign in / Sign up

Export Citation Format

Share Document