Non-reflecting free field boundary conditions for the lattice Boltzmann method

We present boundary conditions for the lattice Boltzmann method which suppress the reflection of sound waves. The partial density of a sound wave is approximated by low-pass filtering, an unknown population of the distribution function on the boundary node is set by adapting the momentum correspondingly to the wave resistance of the pressure wave. The results of an implementation in 1D are compared to the corresponding free field simulation showing good agreement for inviscid flows. An implementation of both velocity and pressure boundary conditions for the 2D case is shown. The suppression of waves approaching the boundary is hereby independent of the incident angle.     «

We present boundary conditions for the lattice Boltzmann method which suppress the reflection of sound waves. The partial density of a sound wave is approximated by low-pass filtering, an unknown population of the distribution function on the boundary node is set by adapting the momentum correspondingly to the wave resistance of the pressure wave. The results of an implementation in 1D are compared to the corresponding free field simulation showing good agreement for inviscid flows. An implement...     »