scholarly journals Effects of viscoelasticity on shear-thickening in dilute suspensions in a viscoelastic fluid

Soft Matter ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 728-737
Author(s):  
Yuki Matsuoka ◽  
Yasuya Nakayama ◽  
Toshihisa Kajiwara
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Viscoelastic Fluid ◽  
Shear Thickening ◽  
Profile Method ◽  
Fluid Elasticity ◽  
Simulation Based ◽  
Dilute Suspensions ◽  
Smoothed Profile Method

We investigate previously unclarified effects of fluid elasticity on shear-thickening in dilute suspensions in an Oldroyd-B viscoelastic fluid using a novel direct numerical simulation based on the smoothed profile method.

Direct numerical simulation–based Reynolds-averaged closure for bubble-induced turbulence

2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Tian Ma ◽  
Claudio Santarelli ◽  
Thomas Ziegenhein ◽  
Dirk Lucas ◽  
Jochen Fröhlich
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Simulation Based

Direct Numerical Simulation of Drops in Three Dimensional Viscoelastic Simple Shear Flows

2001 ◽  
Author(s):  
Shriram B. Pillapakkam ◽  
Pushpendra Singh
Keyword(s):  
Numerical Simulation ◽  
Shear Flow ◽  
Direct Numerical Simulation ◽  
Viscoelastic Fluid ◽  
Simple Shear ◽  
Polymer Concentration ◽  
Three Dimensional ◽  
Simple Shear Flow ◽  
Splitting Technique

Abstract A three dimensional finite element scheme for Direct Numerical Simulation (DNS) of viscoelastic two phase flows is implemented. The scheme uses the Level Set Method to track the interface and the Marchuk-Yanenko operator splitting technique to decouple the difficulties associated with the governing equations. Using this numerical scheme, the shape of Newtonian drops in a simple shear flow of viscoelastic fluid and vice versa are analyzed as a function of Capillary number, Deborah number and polymer concentration. The viscoelastic fluid is modeled via the Oldroyd-B model. The role of viscoelastic stresses in deformation of a drop subjected to simple shear flow and its effect on the steady state shape is analyzed. Our results compare favorably with existing experimental data and also help in understanding the role of viscoelastic stresses in drop deformation.

Direct numerical simulation of the drag-reducing turbulent boundary layer of viscoelastic fluid

2007 ◽  
Vol 19 (7) ◽  
pp. 075106 ◽  
Author(s):  
Shinji Tamano ◽  
Motoyuki Itoh ◽  
Kenichi Hoshizaki ◽  
Kazuhiko Yokota
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Direct Numerical Simulation ◽  
Viscoelastic Fluid

Direct numerical simulation of strong compression of the axisymmetric gas cavity in a liquid

2007 ◽  
Vol 5 ◽  
pp. 73-78
Author(s):  
A.A. Aganin ◽  
T.F. Khalitova ◽  
N.A. Khismatullina
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Gas Bubble ◽  
Godunov Scheme ◽  
Smooth Solutions ◽  
Order Accuracy ◽  
First Order ◽  
Simulation Based ◽  
Strong Compression ◽  
Gas Cavity

A technique for computing strong compression of an axisymmetric gas bubble in a liquid by direct numerical simulation based on the equations of fluid dynamics is presented. This technique uses a scheme of the second-order accuracy in space and time for smooth solutions. Some results of numerical investigation of efficiency of this technique are given. It is established that this technique is much more effective than the classical first order accurate Godunov scheme widely known in the literature.

scholarly journals Turbulent Bubble-Laden Channel Flow of Power-Law Fluids: A Direct Numerical Simulation Study

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 40
Author(s):  
Felix Bräuer ◽  
Elias Trautner ◽  
Josef Hasslberger ◽  
Paolo Cifani ◽  
Markus Klein
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Power Law ◽  
Volume Fraction ◽  
Vertical Channel ◽  
Shear Thickening ◽  
Volumetric Flow Rate ◽  
Mean Velocity ◽  
Power Law Fluids ◽  
Gas Volume

The influence of non-Newtonian fluid behavior on the flow statistics of turbulent bubble-laden downflow in a vertical channel is investigated. A Direct Numerical Simulation (DNS) study is conducted for power-law fluids with power-law indexes of 0.7 (shear-thinning), 1 (Newtonian) and 1.3 (shear-thickening) in the liquid phase at a gas volume fraction of 6%. The flow is driven downward by a constant volumetric flow rate corresponding to a friction Reynolds number of Reτ≈127.3. The Eötvös number is varied between Eo=0.3125 and Eo=3.75 in order to investigate the influence of quasi-spherical as well as wobbling bubbles and thus the interplay of the bubble deformability with the power-law behavior of the liquid bulk. The resulting first- and second-order fluid statistics, i.e., the gas fraction, mean velocity and velocity fluctuation profiles across the channel, show clear trends in reply to varying power-law indexes. In addition, it was observed that the bubble oscillations increase with decreasing power-law index. In the channel core, the bubbles significantly increase the dissipation rate, which, in contrast to its behavior at the wall, shows similar orders of magnitude for all power-law indexes.

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