Plume dispersion simulation using locally mesh-refined Lattice Boltzmann Method

Onodera, Naoyuki   ; Idomura, Yasuhiro   

A real-time simulation of the environmental dynamics of radioactive substances is very important from the view-point of nuclear security. Since a lot of tall buildings and complex structures make the air flow turbulent in urban cities, large-scale CFD simulations are needed. To this end, a CFD code based on a Lattice Boltzmann Method (LBM) with a block-based Adaptive Mesh Refinement (AMR) method is developed. As the conventional LBM based on a single relaxation time collision operator often becomes numerically unstable at high Reynolds number, we apply a cumulant collision operator. The code is validated against a wind tunnel test, which was released from the National Institute of Advanced Industrial Science and Technology. The computational grids are subdivided by the AMR method, and the total number of grid points is reduced to less than 10% compared to the finest mesh. In spite of the fewer grid points, the turbulent statistics are in good agreement with the experiment data.