scholarly journals Deformation of a Capsule in a Power-Law Shear Flow

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Fang-Bao Tian
Keyword(s):  
Reynolds Number ◽  
Shear Rate ◽  
Shear Flow ◽  
Lattice Boltzmann Method ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Immersed Boundary ◽  
Power Law Fluid ◽  
Boltzmann Method ◽  
Power Law Index

An immersed boundary-lattice Boltzmann method is developed for fluid-structure interactions involving non-Newtonian fluids (e.g., power-law fluid). In this method, the flexible structure (e.g., capsule) dynamics and the fluid dynamics are coupled by using the immersed boundary method. The incompressible viscous power-law fluid motion is obtained by solving the lattice Boltzmann equation. The non-Newtonian rheology is achieved by using a shear rate-dependant relaxation time in the lattice Boltzmann method. The non-Newtonian flow solver is then validated by considering a power-law flow in a straight channel which is one of the benchmark problems to validate an in-house solver. The numerical results present a good agreement with the analytical solutions for various values of power-law index. Finally, we apply this method to study the deformation of a capsule in a power-law shear flow by varying the Reynolds number from 0.025 to 0.1, dimensionless shear rate from 0.004 to 0.1, and power-law index from 0.2 to 1.8. It is found that the deformation of the capsule increases with the power-law index for different Reynolds numbers and nondimensional shear rates. In addition, the Reynolds number does not have significant effect on the capsule deformation in the flow regime considered. Moreover, the power-law index effect is stronger for larger dimensionless shear rate compared to smaller values.

scholarly journals Study on flow of power-law fluid through an infinite array of circular cylinders with immersed boundary-lattice Boltzmann method

2012 ◽  
Vol 16 (5) ◽  
pp. 1451-1455
Author(s):  
Ye-Long Wang ◽  
Xue-Ming Shao
Keyword(s):  
Lattice Boltzmann Method ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Lift Coefficient ◽  
Circular Cylinders ◽  
Immersed Boundary ◽  
Particulate Flows ◽  
Power Law Fluid ◽  
Infinite Array ◽  
Boltzmann Method

A direct forcing method for the simulation of particulate flows based on immersed boundary-lattice Boltzmann method is used to study the flow of power-law fluid through an infinite array of circular cylinders with cylinder separations of 20a (a is the cylinder radius) with laminar shedding behind cylinders. Time averaged drag coefficient, maximum of lift coefficient and Strouhal number are given out with the power-law index in the range of 0.4 ? n ? 1.8 and Re in the range of 50 ? Re ? 140.

Simulation of Power-Law Fluid Flows in Two-Dimensional Square Cavity Using Multi-Relaxation-Time Lattice Boltzmann Method

2014 ◽  
Vol 15 (1) ◽  
pp. 265-284 ◽  
Author(s):  
Qiuxiang Li ◽  
Ning Hong ◽  
Baochang Shi ◽  
Zhenhua Chai
Keyword(s):  
Reynolds Number ◽  
Relaxation Time ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Fluid Flows ◽  
Two Dimensional ◽  
Square Cavity ◽  
Power Law Fluid ◽  
Boltzmann Method ◽  
Power Law Index

AbstractIn this paper, the power-law fluid flows in a two-dimensional square cavity are investigated in detail with multi-relaxation-time lattice Boltzmann method (MRT-LBM). The influence of the Reynolds number (Re) and the power-law index (n) on the vortex strength, vortex position and velocity distribution are extensively studied. In our numerical simulations, Re is varied from 100 to 10000, and n is ranged from 0.25 to 1.75, covering both cases of shear-thinning and shear-thickening. Compared with the Newtonian fluid, numerical results show that the flow structure and number of vortex of power-law fluid are not only dependent on the Reynolds number, but also related to power-law index.

Study of flapping filaments using the immersed boundary-lattice Boltzmann method

2018 ◽  
Vol 89 (15) ◽  
pp. 3127-3136
Author(s):  
Zhengdao Wang ◽  
Yi Kun Wei ◽  
Yuehong Qian
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Resonance Phenomenon ◽  
Discrete Equation ◽  
Immersed Boundary ◽  
Modified Method ◽  
Wide Range ◽  
Motion Characteristics ◽  
Boltzmann Method

In this study, flow over a flexible filament under a wide range of parameters is simulated using the immersed boundary-lattice Boltzmann method (IB-LBM). The leading end of the filament is fixed in the flow field and the trailing end is free to flap. To execute the simulation, we combine the IB-LBM and a semi-implicit discrete equation of force on the filament to better satisfy the boundary condition. After some numerical simulations validating the modified method, the motion of flexible filaments is examined with different dimensionless bending coefficients ([Formula: see text]) and Reynolds numbers ([Formula: see text]). From the trajectory of the flapping filament, different flapping modes are found. When the parameter is between that of two modes, the anti-resonance phenomenon is observed. Numerical results show that the dimensionless bending coefficient and Reynolds number both affect the flapping motion, but in different ways. The dimensionless bending coefficient mainly affects the mode of the flapping, while the Reynolds number mainly affects the perturbation to the filament motion, which is related to the motivation of this system. Some other motion characteristics, for example, the function of amplitude and perturbation propagation, are also discussed in this work.

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.

On determining the power-law fluid friction factor in a partially porous channel using the lattice Boltzmann method

2020 ◽  
Vol 32 (9) ◽  
pp. 093104
Author(s):  
Rodrigo E. C. P. Meira ◽  
Fernando C. De Lai ◽  
Cezar O. R. Negrão ◽  
Silvio L. M. Junqueira
Keyword(s):  
Lattice Boltzmann Method ◽  
Friction Factor ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Porous Channel ◽  
Power Law Fluid ◽  
Fluid Friction ◽  
Boltzmann Method
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