A peridynamics-immersed boundary-lattice Boltzmann method for fluid-structure interaction analysis

Fluid-structure interaction problems (FSI) are ubiquitous in nature and industrial production. Numerical simulation has been taken as an effective method for fluid-structure interaction analysis. To accurately and efficiently simulate the deformation and fracture of structure induced by fluid-structure interactions, a novel PD-IB-LBM is proposed. Specifically, the structural deformation and fracture is described by the improved bond-based peridynamic (PD) model with an attenuation kernel function and surface effect correction, and the fluid flow is modeled by the lattice Boltzmann method (LBM), together with immersed boundary method (IBM) as a solid bridge to realize the bi-directional coupling at the fluid-solid interface. Therefore, the generation of body conformal mesh and mesh reconstruction are avoided, and the damage and fracture of structure and the movement of the fluid can be well described. In addition, the velocity correction of fluid and solid is achieved by solving a linear system of equations derived from IBM, which eliminates the trouble of iterative solution between fluid and solid for the traditional coupling method. The proposed model is validated through the simulation of flow past a circular cylinder, a rotating ring in a square fluid, and the fracture of the beam in a fluid tunnel. The simulation results show that the proposed PD-IB-LBM model and algorithm can effectively predict the discontinuous mechanical behaviors such as damage and crack propagation of structure under complex fluid motion.