A LBM-based Hybrid Method for Simulating Flows with Rigid and Deformable Particles

The lattice Boltzmann method (LBM) has been widely used in the study of particulate flows, which have a wide range of applications in fundamental research as well as engineering practice. In this paper, a LBM-based hybrid method is presented for the simulations of resolved particle-laden flows. This method combines the most desirable features of the lattice Boltzmann method and the immersed boundary method by using a regular Eulerian mesh for the flow domain and a Lagrangian mesh for the moving particles in the flow field. The impact of the moving particles to the flow field is considered by introducing a force density term into the framework of lattice Boltzmann method. For the rigid particles, the force density term is simply computed by the concept of momentum exchange at the particle boundary point. While for the deformable particles, a thin-shell model within the framework of the Kirchhoff-Love theory is adopted to compute the forces acting on the shell middle surface during the deformation. This hybrid approach provides a simple and efficient way to treat particle-fluid boundary conditions and is quite suitable for tracking a large group of particles in the flow. The present method will be used to study the particle and cell controls and manipulations in micro-fluidics.