Combined interface boundary condition method for fluid-structure interaction: Some improvements and extensions

The combined interface boundary condition (CIBC) method devises the increments to correct traditional interface conditions for partitioned computation of fluid-structure interaction. However, the restricted use of the CIBC method has been realized recently. In this paper we present some improvements and extensions of the CIBC method as follows: (1) the method is reformulated in the general situation by using the complete fluid stress tensor; (2) the structural traction rate, which results in the inconsistency in the interfacial traction and may cause the loss of numerical accuracy, is totally removed from the CIBC formulation via a simple revision; (3) we analyze the instability source due to the CIBC compensation and propose an approach to recover the two-sided corrections for Dirichlet and Neumann interface conditions; (4) the CIBC method is extended to the generalized planar rigid-body motion. A novel CBS-based partitioned semi-implicit coupling approach is adopted to couple different fields within the nondimensional ALE finite element framework. The interaction between incompressible flows and a rigid/flexible body is numerically simulated to demonstrate the validity of the developed method. The reasonable agreement is disclosed between the present and available data.