Björn Hübner

Space-Time Finite Elements for Fluid-Structure Interaction

A numerical method for the analysis of fluid-structure interaction in the areas of building aeroelasticity and building-water interaction is presented. In order to achieve optimal convergence of the solution a consistent space-time discretization and a strong coupling algorithm is applied to the highly nonlinear problem.

Fluid-structure coupling within a monolithic model involving free surface flows

Publisher Summary This chapter presents a numerical method for the analysis of fluid-structure interaction problems with free surface flows. To achieve optimal convergence of the solution, a consistent space-time discretization for both continua and a strong coupling algorithm is applied to the highly nonlinear problem. The volume of fluid method is used for free surface flows if the moving space-time mesh becomes too distorted. A consistent finite-element model of the multifield problem composed of geometrically nonlinear elastic structure, incompressible viscous flow field, and coupling conditions is developed. The formulation of the coupling conditions on the interface uses boundary tractions as additional variables to enforce momentum conservation between fluid and structure. The strong coupling algorithm, together with in time-adaptable space-time elements, enforces the conservation of momentum and mechanical energy at the fluid structure interface.

Simultaneous Solution to Viscous Fluid Flow Interacting with Large Amplitude Structural Vibrations

The paper presents a simultaneous solution procedure for fluid-structure interaction problems with application to building aeroelasticity. The structural motion is described with a geometrically nonlinear theory, and the flow field is modeled with the incompressible Navier-Stokes equations. The space-time finite element method is applied to both continua leading to a consistent discretization of fluid and structure. In order to enforce momentum conservation between both continua, a weighted residual formulation of coupling conditions is introduced. The monolithic approach ensures high convergence and accuracy of the solution and allows coupled stability analyses. A numerical example of membrane flutter demonstrates efficiency and versatility of the presented methodology.