Application of synthetic jets to low Reynolds number biosensor microfluidic flows for enhanced mixing: a numerical study using the lattice Boltzmann method

2002 ◽  
Author(s):  
Thomas S. Mautner
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Low Reynolds Number ◽  
Synthetic Jets ◽  
Microfluidic Flows ◽  
Low Reynolds ◽  
Boltzmann Method

Determining Flow Mixing Characteristics in Low Reynolds Numbers Micro Wavy Channels by the Lattice-Boltzmann Method

2010 ◽  
Author(s):  
Amador M. Guzma´n ◽  
Mari´a Gabriela Quezada ◽  
Luis E. Sanhueza ◽  
Andre´s J. Di´az
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Low Reynolds Number ◽  
Mixing Enhancement ◽  
Flow Mixing ◽  
Mixing Characteristics ◽  
Low Reynolds ◽  
Wavy Channels ◽  
Boltzmann Method

The Eulerian and Lagrangian flow mixing characteristics in a two-dimensional (2D) micro wavy channels for low Reynolds number have been investigated using the Lattice-Boltzmann method (LBM) for solving the governing Boltzmann Transport Equation (BTE). Numerical simulations of a Newtonian compressible flow for Reynolds number flow regimes lower than Re = 0.505 are performed using a computational model of a symmetric wavy channel with many cavities and a geometrical aspect ratio of r = a/(2L) = 0.375, where a is the amplitude of the sinusoidal wall, and L is the cavity periodic length. The Eulerian flow characteristics are determined for different Knudsen numbers with the objective of characterizing time dependent velocity and flow patterns. Then, the Lagrangian characteristics are obtained by integrating the Eulerian velocity field. Thousands of massless fluid particles are used for determining fluid particle Lagrangian trajectories, stretching fields and Lagrangian Lyapunov exponents associated to possible evidences of flow mixing enhancement in different regions of the micro channel. The numerical results demonstrate that low Reynolds number compressible flows in micro wavy channels develop Lagrangian characteristics and stretching field that can lead later to flow mixing enhancement characteristics in an electroosmotic flow in microchannels with wavy, grooved and/or any other surface pattering on the channels walls.

Development of Evaluation Method for Cold Trap in Fast Breeder Reactor: Part 1 — Numerical Analysis of Impurity Precipitation on Mesh Wire

2017 ◽  
Author(s):  
Akinori Tamura ◽  
Shiro Takahashi ◽  
Hiroyuki Nakata ◽  
Akio Takota
Keyword(s):  
Reynolds Number ◽  
Numerical Analysis ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Evaluation Method ◽  
Low Reynolds Number ◽  
Cold Trap ◽  
Precipitation Model ◽  
Low Reynolds ◽  
Boltzmann Method

A cold trap is one of the important components in the Fast Breeder Reactor (FBR) to control oxygen and hydrogen concentration of liquid sodium. For more accurate evaluation of the cold trap performance, we have started a research program to develop the evaluation method based on the 3D numerical analysis. Our evaluation method consists of two steps: one is a numerical analysis of sodium compound deposition on the mesh wires; the other is a numerical analysis of the sodium flow in the cold trap where the effect of the sodium compound deposition is considered as local pressure loss increment. In this study, we have focused on the development of the numerical analysis method of the sodium compound deposition on the mesh wires of the cold trap. As a numerical method, we have adopted the lattice Boltzmann method which is known to be useful for the flow simulation around the complex geometry like the mesh wires. In order to apply the lattice Boltzmann method to the sodium compound deposition simulation around the mesh wire, we proposed a low Reynolds number model and an impurity precipitation model for the conventional lattice Boltzmann method. The low Reynolds number model was validated by a comparison with a theoretical solution of the two-dimensional channel flow. To validate the impurity precipitation model, we conducted a precipitation experiment by using the supersaturated sucrose in the water instead of the liquid sodium with the oxygen and the hydrogen. The comparison between the experiment and the simulation showed good agreement regarding the pressure loss increment. From these results, we confirmed the accuracy of the low Reynolds number model and the impurity precipitation model. The accuracy of our models in the sodium condition will be confirmed in the future study.

A Numerical Study of Jet Propulsion of an Oblate Jellyfish Using a Momentum Exchange-Based Immersed Boundary-Lattice Boltzmann Method

2014 ◽  
Vol 6 (3) ◽  
pp. 307-326 ◽  
Author(s):  
Hai-Zhuan Yuan ◽  
Shi Shu ◽  
Xiao-Dong Niu ◽  
Mingjun Li ◽  
Yang Hu
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Mass Density ◽  
Density Ratio ◽  
Large Mass ◽  
Immersed Boundary ◽  
Momentum Exchange ◽  
Boltzmann Method

AbstractIn present paper, the locomotion of an oblate jellyfish is numerically investigated by using a momentum exchange-based immersed boundary-Lattice Boltzmann method based on a dynamic model describing the oblate jellyfish. The present investigation is agreed fairly well with the previous experimental works. The Reynolds number and the mass density of the jellyfish are found to have significant effects on the locomotion of the oblate jellyfish. Increasing Reynolds number, the motion frequency of the jellyfish becomes slow due to the reduced work done for the pulsations, and decreases and increases before and after the mass density ratio of the jellyfish to the carried fluid is 0.1. The total work increases rapidly at small mass density ratios and slowly increases to a constant value at large mass density ratio. Moreover, as mass density ratio increases, the maximum forward velocity significantly reduces in the contraction stage, while the minimum forward velocity increases in the relaxation stage.

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