High-Gradient Method for the Numerical Simulation of the Continuum Problems with the Strong Discontinues

2021 ◽  
pp. 133-150
Author(s):  
Vladimir V. Demchenko
Keyword(s):  
Numerical Simulation ◽  
Gradient Method ◽  
High Gradient ◽  
The Continuum

Direct Numerical Simulation of Cellular Blood Flow Through a Model Arteriole Bifurcation

2010 ◽  
Author(s):  
Daniel A. Reasor ◽  
Jonathan R. Clausen ◽  
Cyrus K. Aidun
Keyword(s):  
Numerical Simulation ◽  
Blood Flow ◽  
Direct Numerical Simulation ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Particle Level ◽  
Suspension Dynamics ◽  
Flow Through ◽  
Fahraeus Effect ◽  
The Continuum

Blood is composed of a suspension of red blood cells (RBCs) suspended in plasma, and the presence of the RBCs substantially changes the flow characteristics and rheology of these suspensions. The viscosity of blood varies with the hematocrit (volume fraction of RBCs), which is a result not seen in Newtonian fluids. Additionally, RBCs are deformable, which can alter suspension dynamics. Understanding the physics in these flows requires accurately simulating the suspended phase to recover the microscale, and a subsequent analysis of the rheology to ascertain the continuum-level effects caused by the changes at the particle level. The direct numerical simulation of blood flow including RBC migration effects has the capability to resolve the Fåhraeus effect of observing low hematocrit values near walls, the subsequent cell-depleted layer, and the presence of velocity profile blunting due to the distribution of RBCs.

scholarly journals Spatial Limit of CFD Model at Nanometer Scale Geometry: Part I: Capillary Flow

2020 ◽  
Vol 5 (7) ◽  
pp. 795-799
Author(s):  
Simon Mark ◽  
Harry Boyer
Keyword(s):  
Numerical Simulation ◽  
Capillary Flow ◽  
Numerical Models ◽  
New Technology ◽  
Small Scale ◽  
Lab On Chip ◽  
Potential Error ◽  
Passive Flow ◽  
On Chip ◽  
The Continuum

Numerical simulation using computational fluid dynamics has been studied broadly in various fields of applications. Along with the advancement in new technology especially those employing micro or nanoscale geometries or lab-on-chip devices, it is important to understand the efficiency of such numerical models at small geometrical scales. To access any potential error in numerical simulation using CFD, in the present work we report the investigation of capillary driven passive flow inside a channel of varying geometry. The potential error in the results of simulation at a very small scale is accessed by comparing it with the results of theoretical analysis. Hence, establishes a spatial limit of the continuum model for simulation in related applications. This gives new insight to the further study on CFD at nanometers scale geometry.

Numerical simulation of high-gradient magnetic filtration

2016 ◽  
Vol 61 (9) ◽  
pp. 1292-1298 ◽  
Author(s):  
B. A. Gusev ◽  
V. G. Semenov ◽  
V. V. Panchuk
Keyword(s):  
Numerical Simulation ◽  
High Gradient ◽  
Magnetic Filtration

Numerical Simulation of Impingement Air Cooling From LSI Packages With Large Plate Fins by the Penalty Finite Element Method

1997 ◽  
Vol 119 (1) ◽  
pp. 73-77 ◽  
Author(s):  
T. Tanaka ◽  
H. Matsushima ◽  
A. Ueki ◽  
T. Atarashi
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Conjugate Gradient Method ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Computational Time ◽  
Air Cooling ◽  
Large Plate ◽  
Element Method

Steady state three-dimensional incompressible flow analysis based on the two-equation model of turbulence is performed. The finite element method employing the penalty function formulation by Hughes et al. (1979) is used. To reduce the computational time and computer storage, the conjugate gradient method is applied to solve algebraic equations. In applying the conjugate gradient method, the equations are preconditioned so as to arrive at converged solutions effectively. The problem cited in this study is the impingement air cooling of the large scale integrated circuit package with large plate fins. The calculated velocity vectors show good agreement with the result of flow visualization. The calculated temperature distributions also agree well with the experimental temperatures. This suggests the usefulness of this kind of numerical simulation in the research and development of new cooling technologies.

Numerical Simulation of a Suspension of Swimming Micro-Organisms

2007 ◽  
Author(s):  
Takuji Ishikawa ◽  
T. J. Pedley ◽  
Takami Yamaguchi
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Continuum Model ◽  
Diffusion Tensor ◽  
Continuum Models ◽  
Dilute Suspensions ◽  
Plankton Bloom ◽  
Cell Concentrations ◽  
Micro Organisms ◽  
The Continuum

The size of individual micro-organisms is often much smaller than that of the flow field of interest, in an oceanic plankton bloom for instance. In such cases, the suspension of micro-organisms is modelled as a continuum in which the variables are volume-averaged quantities. Continuum models for suspensions of swimming micro-organisms have been proposed for the analysis of phenomena such as bioconvection. However, the continuum models proposed so far are restricted to dilute suspensions, in which cell-cell interactions are negligible. If one wishes to analyze larger cell concentrations, it will be necessary to consider the interactions between micro-organisms. Then the particle stress tensor, the velocities of the micro-organisms and the diffusion tensor in the continuum model will need to be replaced by improved expressions. In this study, we compute the motion of interacting swimming model micro-organisms in periodic suspensions in a fluid otherwise at rest, and discuss the microstructure constructed by micro-organisms.

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