Lattice Boltzmann Simulation of Multiple Bubbles Motion under Gravity

Lattice Boltzmann method (LBM) is employed in the current work to simulate two-phase flows of immiscible fluids over a square obstacle in a 2D computational domain using the Rothman-Keller color gradient model. This model is based on the multiphase Rothman-Keller description, it is used to separate two fluids in flow and to assess its efficacy when treating two fluids in flow over a square obstacle with the objective of reducing turbulence by adjusting the viscosities of the two fluids. This turbulence can cause major problems such as interface tracking techniques in gas-liquid flow and upward or downward co-current flows in pipes. So, the purpose of the study is to replace a single fluid with two fluids of different viscosities by varying these viscosities in order to reduce or completely eliminate the turbulence. The results show that to have stable, parallel and non-overlapping flows behind the obstacle, it is necessary that the difference between the viscosities of the fluids be significant. Also, showing that the increase in the viscosity ratio decreases the time corresponding to the disappearance of the vortices behind the obstacle. The results presented in this work have some general conclusions: For M≥2, the increase in the viscosity difference leads to an increasing of friction between fluids, reducing of average velocity of flow and decreasing the time corresponding to the disappearance of the vortices behind the obstacle. However, for M≤1/2, the opposite occurs.

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“…G is a body force. In our simulation, the body force is added to lattice Boltzmann equation as (Nie et al, 2015):…”

Section: Elimination Of the Unwanted Extra Termmentioning

confidence: 99%

Study of Two Layered Immiscible Fluids Flow in a Channel with Obstacle by Using Lattice Boltzmann RK Color Gradient Model

Channouf

Admi

Jami

et al. 2022

Int. J. Renew. Energy Dev.

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“…In China, Shengwei et al used fluid mechanics theory to study the size, density, distribution, and other characteristics of the bubble [10]. Nie et al used the lattice Boltzmann 2 Mathematical Problems in Engineering method to study the multibubble merging mode and increasing speed [11]. Donghua et al used the improved Reynolds average Navier-Stokes flow model and bubble transport theory to calculate and analyze the number density (BND) distribution of the wake bubble [12].…”

Section: Introductionmentioning

confidence: 99%

Simulation and Statistical Modeling of Acoustic Scattering of Bubble Wakes

Ling-Guo

Zhao

Wang

et al. 2018

Mathematical Problems in Engineering

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Ship wakes are large, exist for a long time, and are difficult to disguise or conceal. These characteristics can be used as an important basis for ship tracking and recognition. However, distinguishing between wakes, underwater targets, and sea surface is a difficult problem that currently limits acoustic wake homing technology. To solve this problem, in this study, from the viewpoint of feature recognition, the effects of bubble radius, air volume fraction, frequency, depth, and other parameters on the group bubble were first investigated. The volume scattering intensity of acoustic wakes at different frequencies and depths was also calculated and analyzed, and the results of our theoretical calculations were verified through an experiment using a multifrequency single wave sonar dock. Subsequently, through the single frequency and multibeam sonar sea trial test, a statistical model of target characteristics with a clear physical mechanism was developed. The developed model can be utilized for the guidance and recognition of acoustic wake targets. Thus, this study lays the foundation for the practical application of acoustic wake guidance.

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“…The motion of dispersed air bubble in its process has been the focus of research for a long time [1]. In the past few decades, a number of experimental investigations [2,3,4] have been performed to understand the basic underlying physics and its hydrodynamics [5]. Based on the empirical relations obtained from experiments, researchers developed various numerical models or computational fluid dynamics (CFD) techniques for this multiphase problem.…”

Section: Introductionmentioning

confidence: 99%

Development of algorithm to model dispersed gas-liquid flow using lattice Boltzmann method

Agarwal,

Ravindra,

Prakash

2017

Preprint

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In this paper, we present the algorithm for the simulation of a single bubble rising in a stagnant liquid using Euler-Lagrangian (EL) approach. The continuous liquid phase is modeled using BGK approximation of lattice Boltzmann method (LBM), and a Lagrangian particle tracking (LPT) approach has been used to model the dispersed gas (bubble) phase. A two-way coupling scheme is implemented for the interface interaction between two phases. The simulation results are compared with the theoretical and experimental data reported in the literature and it was found that the presented modeling technique is in good agreement with the theoretical and experimental data for the relative and terminal velocity of a bubble. We also performed the grid independence test for the current model and the results show that the grid size does not affect the rationality of the results. The stability test has been done by finding the relative velocity of a bubble as a function of time for the different value of dimensionless relaxation frequency. The present study is relevant for understanding the bubble-fluid interaction module and helps to develop the accurate numerical model for bioreactor simulation.

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Lattice Boltzmann Simulation of Multiple Bubbles Motion under Gravity

Cited by 4 publications

References 17 publications

Study of Two Layered Immiscible Fluids Flow in a Channel with Obstacle by Using Lattice Boltzmann RK Color Gradient Model

Study of Two Layered Immiscible Fluids Flow in a Channel with Obstacle by Using Lattice Boltzmann RK Color Gradient Model

Simulation and Statistical Modeling of Acoustic Scattering of Bubble Wakes

Development of algorithm to model dispersed gas-liquid flow using lattice Boltzmann method

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