A novel geometry-adaptive Cartesian grid based immersed boundary–lattice Boltzmann method for fluid–structure interactions at moderate and high Reynolds numbers

2018 ◽  
Vol 375 ◽  
pp. 22-56 ◽  
Author(s):  
Lincheng Xu ◽  
Fang-Bao Tian ◽  
John Young ◽  
Joseph C.S. Lai
Keyword(s):  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Cartesian Grid ◽  
Immersed Boundary ◽  
Fluid Structure Interactions ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
Boltzmann Method ◽  
Adaptive Cartesian Grid ◽  
Grid Based

FLIGHT SIMULATIONS OF A TWO-DIMENSIONAL FLAPPING WING BY THE IB-LBM

2013 ◽  
Vol 25 (01) ◽  
pp. 1340020 ◽  
Author(s):  
YUSUKE KIMURA ◽  
KOSUKE SUZUKI ◽  
TAKAJI INAMURO
Keyword(s):  
Rotational Motion ◽  
Lattice Boltzmann ◽  
Translational Motion ◽  
Reynolds Numbers ◽  
Flapping Wings ◽  
Immersed Boundary ◽  
High Reynolds ◽  
The Stability ◽  
Boltzmann Method ◽  
Flight Simulations

The stability of flight by flapping wings is investigated by using the immersed boundary-lattice Boltzmann method (IB-LBM). First, the rotational motion with an initial small disturbance is computed, and it is found that the rotational motion is unstable for high Reynolds numbers. Second, we show simple ways to control the rotational and translational motion by bending or flapping the tip of the wing.

Two-Dimensional Simulations of Turbulent Flow Past a Row of Cylinders using Lattice Boltzmann Method

2017 ◽  
Vol 14 (01) ◽  
pp. 1750002 ◽  
Author(s):  
Yi-Kun Wei ◽  
Xu-Qu Hu
Keyword(s):  
Lattice Boltzmann Method ◽  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Passive Scalar ◽  
Two Dimensional ◽  
Flow Past ◽  
High Reynolds ◽  
An Array Of Cylinders ◽  
Boltzmann Method

Two-dimensional simulations of channel flow past an array of cylinders are carried out at high Reynolds numbers. Considering the thickness fluctuating effect on the equation of motion, a modified lattice Boltzmann method (LBM) is proposed. Special attention is paid to investigate the thickness fluctuations and vortex shedding mechanisms between 11 cylinders. Results for the velocity and vorticity differences are provided, as well as for the energy density and enstrophy spectra. The numerical results coincide very well with some published experimental data that was obtained by turbulent soap films. The spectra extracted from the velocity and vorticity fields are displayed from simulations, along with the thickness fluctuation spectrum H(k). Our results show that the statistics of thickness fluctuations resemble closely those of a passive scalar in turbulent flows.

scholarly journals Lattice Boltzmann Method Simulations of High Reynolds Number Flows Past Porous Obstacles

2019 ◽  
Vol 11 (03) ◽  
pp. 1950028 ◽  
Author(s):  
N. M. Sangtani Lakhwani ◽  
F. C. G. A. Nicolleau ◽  
W. Brevis
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
High Reynolds Number ◽  
Reynolds Numbers ◽  
Navier Stokes Equation ◽  
High Reynolds ◽  
Boltzmann Method ◽  
Reynolds Number Flows

Lattice Boltzmann Method (LBM) simulations for turbulent flows over fractal and non-fractal obstacles are presented. The wake hydrodynamics are compared and discussed in terms of flow relaxation, Strouhal numbers and wake length for different Reynolds numbers. Three obstacle topologies are studied, Solid (SS), Porous Regular (PR) and Porous Fractal (FR). In particular, we observe that the oscillation present in the case of the solid square can be annihilated or only pushed downstream depending on the topology of the porous obstacle. The LBM is implemented over a range of four Reynolds numbers from 12,352 to 49,410. The suitability of LBM for these high Reynolds number cases is studied. Its results are compared to available experimental data and published literature. Compelling agreements between all three tested obstacles show a significant validation of LBM as a tool to investigate high Reynolds number flows in complex geometries. This is particularly important as the LBM method is much less time consuming than a classical Navier–Stokes equation-based computing method and high Reynolds numbers need to be achieved with enough details (i.e., resolution) to predict for example canopy flows.

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