An LBM-FEM robust and efficient fluid–structure coupling scheme for partitioned numerical simulation of blood flow-aortic valve interaction

This paper presents a novel partitioned coupling scheme for the numerical simulation of Fluid-Structure Interaction (FSI) problems. The proposed method couples the lattice Boltzmann method for fluid dynamics with the finite element method for solid mechanics using the immersed boundary method. The partitioned framework enables separate time integration of the fluid and solid sub-domains, offering significant flexibility in the coupling process. Numerical stability is enhanced through an interface force prediction technique inspired by the strong coupling scheme of Li et al. (2022) , ensuring both robustness and computational efficiency. This approach effectively handles complex FSI problems, particularly in biomechanics. The scheme has been validated through the three-dimensional flapping flag benchmark test, demonstrating excellent agreement with reference results. Additionally, it has been successfully applied to simulate the interaction between pulsatile blood flows and the deformable leaflets of an artificial aortic valve. Compared with existing numerical and experimental studies, the proposed scheme delivers comparable accuracy while achieving nearly fourfold efficiency improvements over the previous strong coupling method.