scholarly journals An absorbing boundary condition for the lattice Boltzmann method based on the perfectly matched layer

2012 ◽  
Vol 68 ◽  
pp. 203-218 ◽  
Author(s):  
A. Najafi-Yazdi ◽  
L. Mongeau
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Perfectly Matched Layer ◽  
Absorbing Boundary Condition ◽  
Absorbing Boundary ◽  
Boltzmann Method

An Absorbing Boundary Condition Based on Perfectly Matched Layer Technique Combined with Discontinuous Galerkin Boltzmann Method for Low Mach Number Flow Noise

2018 ◽  
Vol 26 (04) ◽  
pp. 1850011 ◽  
Author(s):  
Weidong Shao ◽  
Jun Li
Keyword(s):  
Boundary Condition ◽  
Discontinuous Galerkin ◽  
Perfectly Matched Layer ◽  
Absorbing Boundary Condition ◽  
Time Behavior ◽  
Computational Domain ◽  
Mean Flow ◽  
Absorbing Boundary ◽  
Flow Noise ◽  
Boltzmann Method

For flow noise simulations, the nonreflecting boundary condition (NRBC) is significant to confine the computational domain to a small domain. Lattice Boltzmann method (LBM) has advantages for noise because of its low dissipation, but is limited to the uniform grid. In this paper, an absorbing boundary condition (ABC) based on perfectly matched layer (PML) technique is introduced to LBM. Then PML stability is analyzed and a new strategy is developed to achieve robustness. Invoking the decoupling time integration, the underlying equation for streaming is solved with the nodal discontinuous Galerkin method. Benchmark acoustic problems were used to demonstrate the PML absorption. Moreover, PML parameters, long time behavior and inhomogeneous pseudo mean flow are discussed. The methodology appears to work very well and would be hoped for practical flow noise computation.

Aero-Acoustics Computations of Square Cylinder Using the Lattice Boltzmann Method

2013 ◽  
Vol 444-445 ◽  
pp. 400-405
Author(s):  
Hai Qing Si ◽  
Bing Wang ◽  
Yan Shi ◽  
Xiao Jun Wu
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Acoustic Waves ◽  
Absorbing Boundary Condition ◽  
Aerodynamic Noise ◽  
Square Cylinder ◽  
Absorbing Boundary ◽  
Wall Boundary Conditions ◽  
Extrapolation Scheme ◽  
Boltzmann Method

In this paper the ability of the Lattice Boltzmann Method (LBM) is investigated for simulating acoustic problems, especially for the propagation of acoustic waves in a wall bounded region. To treat the wall boundary conditions, a non-equilibrium extrapolation scheme for the LBM is adopted. LBM is next applied to simulate the complex aerodynamic noise generated from a square cylinder. In order to efficiently suppress the disturbances at the computational boundaries, the improved absorbing boundary condition (IABC) is developed in this paper. To validate the flow and acoustic solution of a square cylinder, comparisons between the present LBM and the previous studies are carried out. It is demonstrated that the LBM can efficiently simulate the noise generated from a square cylinder.

scholarly journals Involving the Navier–Stokes equations in the derivation of boundary conditions for the lattice Boltzmann method

2011 ◽  
Vol 369 (1944) ◽  
pp. 2184-2192 ◽  
Author(s):  
Joris C. G. Verschaeve
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Slip Boundary Condition ◽  
Navier Stokes ◽  
Grid Spacing ◽  
Navier Stokes Equations ◽  
Slip Boundary ◽  
Boltzmann Method

By means of the continuity equation of the incompressible Navier–Stokes equations, additional physical arguments for the derivation of a formulation of the no-slip boundary condition for the lattice Boltzmann method for straight walls at rest are obtained. This leads to a boundary condition that is second-order accurate with respect to the grid spacing and conserves mass. In addition, the boundary condition is stable for relaxation frequencies close to two.

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