A finite-element/boundary-element method for large-displacement fluid–structure interaction with potential flow

This work concerns the interaction of light membrane structures enclosing incompressible fluids. Large displacements and collapsed boundaries (initially slender subdomains) are characteristic of this class of problems. A finite-element/boundary-element (FE/BE) coupled discretization is presented as an enabling technology, addressing these challenges by avoiding volumetric meshing as required by arbitrary Lagrangian Eulerian or immersed boundary type methods. The presented formulation includes a compatibility condition, to which a physical interpretation is given; and a regularizing bending stiffness, observed to be necessary from both the theoretical (well-posedness) and numerical (stability) point of view. A cheap contact load is designed to deal with possibly complex geometries, reusing already computed discrete boundary element kernels. Numerical experiments show the capabilities of the proposed scheme.