Parallel Multi-Layer Lattice Boltzmann Method with Load-Balanced Cartesian Grids and Buffer-Driven Bicubic Interpolation

Efficient multi-layer Cartesian grid generation and computation are vital for computational fluid dynamics simulations in complex geometries, where traditional methods face challenges with lengthy grid generation times and numerical dissipation in multi-layer lattice Boltzmann method (LBM). This study proposes an advanced multi-layer LBM computational framework that enhances both accuracy and efficiency by integrating parallel multi-layer grid generation algorithm with a buffer-driven bicubic interpolation algorithm to solve these problems. The proposed parallel Cartesian grid generation algorithm introduces a load-balancing strategy for adaptive grid generation, which automatically adjusts the distribution of cells that intersect with geometry boundaries, balancing the number of intersected cells in different domains across up to three dimensions. To address the challenges of data transfer between different grid layers in multi-layer LBM, a new buffer-driven bicubic interpolation method is introduced. By creating a buffer zone between coarse and fine grids, the interpolation method extends the range of data sources, allowing more neighboring grid points to be used in computations. Numerical experiments demonstrate that these algorithms lead to faster multi-layer grid generation and excellent computational performance in both 2D and 3D cases.