A Lattice Boltzmann-Immersed Boundary-Finite Element Method for Nonlinear Fluid-Solid Interaction Simulation with Moving Objects

A nonlinear finite element method (FEM) was introduced into the immersed boundary (IB) - lattice Boltzmann method (LBM) framework to simulate the nonlinear fluid-solid interactions for moving deformable objects in incompressible fluid flow. The fluid motion is obtained by solving the discrete lattice Boltzmann equation, the moving boundaries of the solids are handled by the IB method, and the nonlinear dynamics of the deforming/moving objects are calculated by nonlinear FEM solvers in which the structural nodes are also set as Lagrangian markers to track the moving boundaries of the structures in IB method. The simulation results indicate that the proposed IB-LBM-FEM simulation framework not only satisfies the nonslip boundary condition well at the boundary points, but also has better accuracy for capturing nonlinearity because of its mature nonlinear FEM solver.