Lattice Boltzmann method on a curvilinear coordinate system: Vortex shedding behind a circular cylinder

1997 ◽  
Vol 56 (1) ◽  
pp. 434-440 ◽  
Author(s):  
Xiaoyi He ◽  
Gary D. Doolen
Keyword(s):  
Circular Cylinder ◽  
Coordinate System ◽  
Lattice Boltzmann Method ◽  
Vortex Shedding ◽  
Lattice Boltzmann ◽  
Curvilinear Coordinate System ◽  
Curvilinear Coordinate ◽  
Boltzmann Method

Simulation of Hypersonic Viscous Flow Past a 2D Circular Cylinder Using Lattice Boltzmann Method

2010 ◽  
Author(s):  
R. Kamali ◽  
A. H. Tabatabaee Frad
Keyword(s):  
Circular Cylinder ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
High Speed ◽  
Fluid Flows ◽  
Boltzmann Distribution ◽  
Equilibrium Distribution Function ◽  
Complex Flows ◽  
Compressible Viscous Flows ◽  
Boltzmann Method

It is known that the Lattice Boltzmann Method is not very effective when it is being used for the high speed compressible viscous flows; especially complex fluid flows around bodies. Different reasons have been reported for this unsuccessfulness; Lacking in required isotropy in the employed lattices and the restriction of having low Mach number in Taylor expansion of the Maxwell Boltzmann distribution as the equilibrium distribution function, might be mentioned as the most important ones. In present study, a new numerical method based on Li et al. scheme is introduced which enables the Lattice BoltzmannMethod to stably simulate the complex flows around a 2D circular cylinder. Furthermore, more stable implementation of boundary conditions in Lattice Boltzmann method is discussed.

Numerical Simulation on Mean Flow past a Circular Cylinder Based on the Lattice Boltzmann Method

2011 ◽  
Vol 105-107 ◽  
pp. 2307-2310
Author(s):  
Jian Ping Yu ◽  
Shu Rong Yu ◽  
Xing Wang Liu
Keyword(s):  
Circular Cylinder ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Mean Flow ◽  
Experiment Data ◽  
Data Simulation ◽  
Lattice Boltzmann Methods ◽  
Flow Past ◽  
Computational Fluid Dynamics Cfd ◽  
Boltzmann Method

Lattice Boltzmann methods (LBM) have become an alternative to conventional computational fluid dynamics (CFD) methods for various systems. In this paper, flow field of mean flow past a circular cylinder was simulated based on the lattice Boltzmann method. The streamline of air past the cylinder illuminated that the fluid adhere on the boundary and doesn’t separate from the surface of cylinder when Re number less than 5. When Re number equal 40, flow separated to form a pair of recirculating eddies can be observed. With the Re number increasing, the trailing vortex length is growth accordingly. When Re number come up to 80, the trailing vortex begin to shed regularly. This result is consistent with the experiment data. Drag coefficient that fluid act on the surface of cylinder was calculated. The calculated results were same as the experiment data. Simulation indicate that LBM can simulate the vortex taking place and shedding effectively.

FLOW EFFECT AROUND TWO SQUARE CYLINDERS ARRANGED SIDE BY SIDE USING LATTICE BOLTZMANN METHOD

2008 ◽  
Vol 19 (11) ◽  
pp. 1683-1694 ◽  
Author(s):  
YONG RAO ◽  
YUSHAN NI ◽  
CHAOFENG LIU
Keyword(s):  
Lattice Boltzmann Method ◽  
Vortex Shedding ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Small Space ◽  
Flip Flop ◽  
Drag And Lift Coefficients ◽  
Square Cylinders ◽  
Drag And Lift ◽  
Boltzmann Method

The flow around two square cylinders arranged side by side has been investigated through lattice Boltzmann method under different Reynolds numbers and various space ratios (s = d/D, d is the separation distance between two cylinders, D is the characteristic length) from 1.0, 1.1 to 2.7, including 18 space ratios. It is found that the flip-flop regime occurs at small space ratios and the synchronized regime occurs at large space ratios. Wide and narrow wakes at small spacing are formed and intermittently change behind the cylinders, and the biased flow in the gap is bistable. The frequency of vortex shedding is different in two wakes. The upper frequency is smaller than the lower frequency for small space ratios (s < 1.4), and the time-averaged drag and lift coefficients of cylinders are also different. When the space ratios increase, two distinct vortex streets occur behind the cylinders, and the frequency of vortex shedding is almost equal in two wakes. Also the difference of time-averaged drag and lift coefficients of the cylinders decreases with the increase in space ratios; in this case the flow shows synchronized regime. The transition between flip-flop and synchronized regimes occurs at s = 1.5. When s < 1.5, the flow shows flip-flop regime; otherwise, it shows synchronized regime. When s = 2.0 and 2.5, the curves for the time-averaged drag and lift coefficient with different Reynolds numbers are smooth. When s = 1.5 and 1.8, the curves are also smooth under Re ≤ 140, but that will be fluctuant under Re > 140 because of the nonlinear interaction between the wakes, and the instability of flow becomes stronger with the increase in Reynolds numbers. On the other hand, the vortex shedding type from the cylinder occurs in-phase when s < 2.5 and s = 2.5 for Re < 190, whereas that occurs anti-phase when s = 2.5 for Re ≥190. In addition, the pressure varies a little on the left surfaces and greatly on the right surfaces of both cylinders with the increase in Reynolds number at s = 2.5.

scholarly journals Effects of Wheel Rotation on Long-Period Wake Dynamics of the DrivAer Fastback Model

Fluids ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Matthew Aultman ◽  
Rodrigo Auza-Gutierrez ◽  
Kevin Disotell ◽  
Lian Duan
Keyword(s):  
Lattice Boltzmann Method ◽  
Motion Sickness ◽  
Vortex Shedding ◽  
Lattice Boltzmann ◽  
Low Frequency ◽  
Low Pressure ◽  
Side Force ◽  
Long Period ◽  
Total Vehicle ◽  
Boltzmann Method

Lattice Boltzmann method (LBM) simulations were performed to capture the long-period dynamics within the wake of a realistic DrivAer fastback model with stationary and rotating wheels. The simulations showed that the wake developed as a low-pressure torus regardless of whether the wheels were rotating. This torus shrank in size on the base in the case of rotating wheels, leading to a reduction in the low-pressure footprint on the base, and consequently a 7% decrease in the total vehicle drag in comparison to the stationary wheels case. Furthermore, the lateral vortex shedding experienced a long-period switching associated with the bi-stability in both the stationary and rotating wheels cases. This bi-stability contributed to low-frequency side force oscillations (<1 Hz) in alignment with the peak motion-sickness-inducing frequency (0.2 Hz).

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