A Temporal Consistent Monolithic Approach to Fluid-Structure Interaction Enabling Single Field Predictors

We present a monolithic approach to large-deformation fluid-structure interaction (FSI) problems that allows for choosing fully implicit, single-step and single-stage time integration schemes in the structure and fluid field independently, and hence is tailored to the needs of the individual field. The independent choice of time integration schemes is achieved by temporal consistent interpolation of the interface traction. To reduce computational costs, we introduce the possibility of field specific predictors in both structure and fluid field. These predictors act on the single fields only. Possible violations of the interface coupling conditions during the predictor step are dealt with within the monolithic solution procedure. We present full details of such a generalized monolithic solution procedure, which is fully consistent in its nonconforming temporal and spatial discretization. The incorporated mortar approach allows for nonmatching spatial discretizations of the fluid and solid domain at the fluid-structure interface and is fully integrated in the resulting monolithic system of equations. The method is applied to a variety of numerical examples. Thereby, temporal convergence rates, the special role of essential boundary conditions at the fluid-structure interface, and the positive effect of predictors are demonstrated and discussed. Emphasis is put on the comparison of different time integration schemes in fluid and structure field, for what the achieved freedom of choice of time integrators is fully exploited.