scholarly journals Shear flow in a three-dimensional complex plasma in microgravity conditions

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
V. Nosenko ◽  
M. Pustylnik ◽  
M. Rubin-Zuzic ◽  
A. M. Lipaev ◽  
A. V. Zobnin ◽  
...  
2018 ◽  
Vol 946 ◽  
pp. 012144 ◽  
Author(s):  
V N Naumkin ◽  
A M Lipaev ◽  
V I Molotkov ◽  
D I Zhukhovitskii ◽  
A D Usachev ◽  
...  

2001 ◽  
Author(s):  
Shriram B. Pillapakkam ◽  
Pushpendra Singh

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.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Min Wang ◽  
Qifeng Guo ◽  
Pengfei Shan ◽  
Meifeng Cai ◽  
Fenhua Ren ◽  
...  

The effects of roughness and normal stress on hydraulic properties of fractures are significant during the coupled shear flow test. Knowing the laws of fluid flow and solute transport in fractures is essential to ensure the nature and safety of geological projects. Although many experiments and numerical simulations of coupled shear flow test have been conducted, there is still a lack of research on using the full Navier-Stokes (N-S) equation to solve the real flow characteristics of fluid in three-dimensional rough fractures. The main purpose of this paper is to study the influence of roughness and normal stress on the fluid flow and solute transport through fractures under the constant normal stiffness boundary condition. Based on the corrected successive random addition (SRA) algorithm, fracture surfaces with different roughness expressed by the Hurst coefficient ( H ) were generated. By applying a shear displacement of 5 mm, the sheared fracture models with normal stresses of 1 MPa, 3 MPa, and 5 MPa were obtained, respectively. The hydraulic characteristics of three-dimensional fractures were analyzed by solving the full N-S equation. The particle tracking method was employed to obtain the breakthrough curves based on the calculated flow field. The numerical method was verified with experimental results. It has been found that, for the same normal stress, the smaller the fracture H value is (i.e., more tough the fracture is), the larger the mechanical aperture is. The ratio of hydraulic aperture to mechanical aperture ( e h / e m ) decreases with the increasing of normal stress. The smaller the H value, the effect of the normal stress on the ratio e h / e m is more significant. The variation of transmissivity of fractures with the flow rate exhibits similar manner with that of e h / e m . With the normal stress and H value increasing, the mean velocity of particles becomes higher and more particles move to the outlet boundary. The dispersive transport behavior becomes obvious when normal stress is larger.


2020 ◽  
Vol 17 (10) ◽  
pp. 2050009
Author(s):  
Sisi Tan ◽  
Mingze Xu

Numerical modeling of whole blood still faces great challenges although significant progress has been achieved in recent decades, because of the large differences of physical and geometric properties among blood components, including red blood cells (RBCs), platelets (PLTs) and white blood cells (WBCs). In this work, we develop a three-dimensional (3D) smoothed particle hydrodynamics (SPH) model to study the whole blood in shear flow. The immersed boundary method (IBM) is used to deal with the interaction between the fluid and cells, which provides a possibility to model the RBCs, PLTs and WBCs simultaneously. The deformation of a small capsule, comparable to a PLT in size, is first examined to show the feasibility of SPH model for the PLTs’ behaviors. The motion of a single RBC in shear flow is then studied, and three typical modes, tank-treading, swinging and tumbling motions, are reproduced, which further confirm the reliability of the SPH model. After that, a simulation of the whole blood in shear flow is carried out, in which the margination trend is observed for both PLTs and WBC. This shows the capability of SPH model with IBM for the simulation of whole blood.


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