Implementation of the compact interpolation within the octree based   Lattice Boltzmann solver Musubi
  A sparse octree based parallel implementation of the lattice Boltzmann method for non-uniform meshes is presented in this paper. To couple grids of different resolutions, a second order accurate compact interpolation is employed and further extended into three dimensions. This compact interpolation requires only four source elements from the adjacent level for both two- and three dimensions. Thus, it reduces the computational and communication overhead in parallel executions. Moreover, the implementation of a weight based domain decomposition algorithm and level-wise elements arrangement are explained in details. The second order convergence of both velocity and strain rate are validated numerically in the Taylor-Green vortex test case. Additionally, the laminar flow around a cylinder at Re = 20, 100 and around a sphere at Re = 100 is investigated. Good agreement between simulated results and those from literature is observed, which provides further evidence for the accuracy of our method. 
Jiaxing Qi, Harald Klimach, Sabine Roller
physics.comp-ph physics.flu-dyn