Abstract

The computation of systems involving the two-way interaction between fluids and lightweight structures is rife with challenges due to differences in the underlying equations and the disparity of the length and time scales involved. In this talk, a new immersed finite element method is introduced for computing fluid-structure interaction problems with geometrically and topologically complex interfaces. The viscous, incompressible fluid is discretized with a fixed Cartesian grid and b-spline basis functions. The two-scale relationship of b-splines is used to implement an intriguingly simple and efficient technique to satisfy the LBB condition. On non-grid-aligned fluid domains and at moving fluid-structure interfaces, the boundary conditions are enforced with a consistent penalty method as originally proposed by Nitsche. In addition, aspecial extrapolation technique is employed to prevent the loss of numerical stability in presence of arbitrarily small cut-cells. In contrast to the fluid, the structure is represented by beams, membranes or thin shells and is discretized with subdivision finite elements. The interaction between the fluid and structure is accomplished by means of a strongly coupled iteration scheme.