We present a fully-integrated lattice Boltzmann (LB) method for fluid--structure interaction (FSI) simulations that efficiently models deformable solids in complex suspensions and active systems. Our Eulerian method (LBRMT) couples finite-strain solids to the LB fluid on the same fixed computational grid with the reference map technique (RMT). An integral part of the LBRMT is a new LB boundary condition for moving deformable interfaces across different densities. With this fully Eulerian solid--fluid coupling, the LBRMT is well-suited for parallelization and simulating multi-body contact without remeshing or extra meshes. We validate its accuracy via a benchmark of a deformable solid in a lid-driven cavity, then showcase its versatility through examples of soft solids rotating and settling. With simulations of complex suspensions mixing, we highlight potentials of the LBRMT for studying collective behavior in soft matter and biofluid dynamics.

翻译：我们提出了一种用于流固耦合（FSI）模拟的完全集成格子玻尔兹曼（LB）方法，该方法可高效模拟复杂悬浮液和活性系统中的可变形固体。我们的欧拉方法（LBRMT）采用参考映射技术（RMT），在相同的固定计算网格上将有限应变固体与LB流体耦合。LBRMT的核心组成部分是一种针对不同密度下移动可变形界面的新型LB边界条件。凭借这种完全欧拉式的流固耦合，LBRMT非常适合并行化处理，并且无需重新划分网格或附加网格即可模拟多体接触。我们通过顶盖驱动空腔中可变形固体的基准测试验证了其准确性，随后通过软固体旋转和沉降的示例展示了其多功能性。通过对复杂悬浮液混合的模拟，我们突出了LBRMT在研究软物质和生物流体动力学中集体行为方面的潜力。