scholarly journals On anti bounce back boundary condition for lattice Boltzmann schemes

2020 ◽  
Vol 79 (3) ◽  
pp. 555-575 ◽  
Author(s):  
François Dubois ◽  
Pierre Lallemand ◽  
Mohamed Mahdi Tekitek
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann ◽  
Bounce Back

Examination of the Slip Boundary Condition by µ-PIV and Lattice Boltzmann Simulations

2002 ◽  
Author(s):  
Derek C. Tretheway ◽  
Luoding Zhu ◽  
Linda Petzold ◽  
Carl D. Meinhart
Keyword(s):  
Boundary Condition ◽  
Shear Rate ◽  
Channel Flow ◽  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Slip Length ◽  
Slip Boundary Condition ◽  
Slip Boundary ◽  
Lattice Boltzmann Simulations ◽  
Bounce Back

This work examines the slip boundary condition by Lattice Boltzmann simulations, addresses the validity of the Navier’s hypothesis that the slip velocity is proportional to the shear rate and compares the Lattice Boltzmann simulations to the experimental results of Tretheway and Meinhart (Phys. of Fluids, 14, L9–L12). The numerical simulation models the boundary condition as the probability, P, of a particle to bounce-back relative to the probability of specular reflection, 1−P. For channel flow, the numerically calculated velocity profiles are consistent with the experimental profiles for both the no-slip and slip cases. No-slip is obtained for a probability of 100% bounce-back, while a probability of 0.03 is required to generate a slip length and slip velocity consistent with the experimental results of Tretheway and Meinhart for a hydrophobic surface. The simulations indicate that for microchannel flow the slip length is nearly constant along the channel walls, while the slip velocity varies with wall position as a results of variations in shear rate. Thus, the resulting velocity profile in a channel flow is more complex than a simple combination of the no-slip solution and slip velocity as is the case for flow between two infinite parallel plates.

SIMULATION OF A SYSTOLIC CYCLE IN A REALISTIC ARTERY WITH THE LATTICE BOLTZMANN BGK METHOD

2003 ◽  
Vol 17 (01n02) ◽  
pp. 95-98 ◽  
Author(s):  
A. M. ARTOLI ◽  
A. G. HOEKSTRA ◽  
P. M. A. SLOOT
Keyword(s):  
Boundary Condition ◽  
Abdominal Aorta ◽  
Lattice Boltzmann ◽  
Systolic Pressure ◽  
Straight Tube ◽  
Pulsatile Blood Flow ◽  
Curved Boundary ◽  
Pressure Cycle ◽  
Human Abdominal Aorta ◽  
Bounce Back

We present an analysis of the accuracy of the lattice Boltzmann BGK (LBGK) method in simulating pulsatile blood flow in a model of the Human Abdominal Aorta. The flow is driven by a systolic pressure cycle. As a benchmark, we consider fully developed pulsatile flow in a straight tube. We compare velocity profiles and shear stress to the analytical Womersley solutions. The accuracy of the bounce-back on the links and a curved boundary condition is compared at different Mach numbers. Preliminary results of systolic flow in the human abdominal aorta are presented.

Lattice Boltzmann Computations of Micro Channel and Micro Orifice Flows

2008 ◽  
Author(s):  
Taiho Yeom ◽  
Ignacio Zea Caloca ◽  
F. W. Chambers
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann ◽  
Slip Flow ◽  
Accommodation Coefficient ◽  
Navier Stokes ◽  
Reflection Factor ◽  
Micro Channel ◽  
Knudsen Numbers ◽  
Micro Flows ◽  
Bounce Back

Filtration in gas micro flows is an important problem complicated by possible slip flow for the filter media and the particles. Slip complicates Navier-Stokes solutions for the flow field. The direct simulation Monte Carlo method and its derivatives can be applied, but they are very complex. The Lattice Boltzmann Method (LBM) appears to offer some advantages for these slip and transitional flows. To evaluate the method, it was used to compute micro channel and micro orifice flows for a range of Knudsen numbers (Kn). The micro orifice simulates an array of micro filter fibers. The Lattice Bhatnagar-Gross-Krook (LBGK) single relaxation time approximation was used with the relaxation parameter accounting for density variations. The effects of different techniques for satisfying slip and no-slip boundary conditions were investigated. Both no-slip bounce-back and slip bounce-back boundary conditions were used. For the slip bounce-back boundary condition, the reflection factor and the accommodation coefficient were applied to improve accuracy. The micro channel computations were performed for conditions matching well-documented compressible slip-flow Navier-Stokes results in the literature. The channel had a length to height ratio of 100 and an inlet to outlet pressure ratio of 2.15. Knudsen numbers of 0.00194, 0.0194, and 0.194 were examined. The bounce-back boundary condition was applied at the top and bottom walls. A reflection factor of 0.85 provided the best agreement with the results in the literature for a Kn = 0.0194. The computed velocity profiles and the nonlinear streamwise pressure profile display excellent agreement with the Navier-Stokes results in the literature at this Knudsen number. At Kn = 0.00194, pure bounce back and bounce back with reflection factor both yield very good results. At Kn = 0.194, the bounce back with reflection factor results exhibit significant deviations from the literature. The accommodation coefficient scheme does not show good results for these micro flows. The reflection factor boundary condition also was applied for the micro orifice flows. The two-dimensional orifice computations were conducted with a 0.6 ratio of the open orifice area to the total area to match results in the literature. The micro orifice LBM results are in good agreement with the literature for Reynolds numbers between 4.8 and 12.5. In summary, the Lattice Boltzmann Method appears promising for micro filter computations, but improvements are needed for larger Knudsen numbers and more sophisticated relaxation time models may be needed for increased compressibility effects at higher Reynolds numbers.

Rarefied transitional flow through diverging nano and microchannels: A TRT lattice Boltzmann study

2018 ◽  
Vol 29 (12) ◽  
pp. 1850117 ◽  
Author(s):  
Soroush Fallah Kharmiani ◽  
Ehsan Roohi
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann ◽  
Pressure Ratio ◽  
Slip Boundary Condition ◽  
Divergence Angle ◽  
Slip Boundary ◽  
Wide Range ◽  
Flow Through ◽  
Slip Coefficients ◽  
Bounce Back

Rarefied isothermal gaseous flow through long diverging micro and nanochannels is investigated in this paper using the two-relaxation-time (TRT) lattice Boltzmann method (LBM). The simulations are performed over a wide range of Knudsen number, pressure ratio, and divergence angle. The Bounce-Back Specular Reflection (BSR) slip boundary condition is applied and is connected to the second-order slip boundary condition coefficients by means of the antisymmetric relaxation time and the bounce-back portion parameter. The effects of the slip coefficients on the wall and centerline Mach numbers, as well as the mass flow rates, are investigated. The numerical results are validated with those of the direct simulation Monte Carlo (DSMC) reported in the literature. The results show that the local pressure distributions are almost independent of the slip coefficients with excellent agreements with DSMC over a wide range of the divergence angle. Our results demonstrate that there is a specific divergence angle at each pressure ratio where the local unbounded Knudsen and, as a result, Mach numbers remain constant along the channel. This observation is almost independent of the slip coefficients, and the underlying reason is that the pressure drop is compensated by an increase in the channel area.

2206 A topology optimization of flow field using lattice Boltzmann method considering bounce-back boundary condition

2013 ◽  
Vol 2013.26 (0) ◽  
pp. _2206-1_-_2206-3_ ◽  
Author(s):  
Takurou MORITA ◽  
Toshiro MATSUMOTO ◽  
Takayuki YAMADA ◽  
Masato YOSHINO ◽  
Toru TAKAHASHI ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Topology Optimization ◽  
Flow Field ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Boltzmann Method ◽  
Bounce Back
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