A non-staggered coupling of finite element and lattice Boltzmann methods via an immersed boundary scheme for fluid-structure interaction

The paper presents a numerical framework for the coupling of finite element and lattice Boltzmann methods for transient problems involving fluid-structure interaction. The solid structure is discretized with the finite element method and integrated in time with the explicit Newmark scheme. The lattice Boltzmann method is used for the simulation of single-component weakly-compressible fluid flows. The two numerical methods are coupled via a direct-forcing immersed boundary method in a non-staggered way. Without subiteration within each time-step, the proposed method can ensure the synchronization of the time integrations, and thus the strong coupling of both subdomains by resolving a linear system of coupling equations at each time-step. Hence the energy transfer at the fluid-solid interface is correct, i.e. neither energy dissipation nor energy injection will occur at the interface, which can retain the numerical stability. A well-known fluid-structure interaction test case is adopted to validate the proposed coupling method. It is shown that the stability of the used numerical schemes can be preserved and a good agreement is found with the reference results. (C) 2016 Elsevier Ltd. All rights reserved.