Fluid-structure interaction

Fluid-structure interaction (FSI) is the mutual influence between a fluid in rest or in flow with a flexible structure, i.e. the fluid forces deform the structure which in turn alters the fluid boundary. Prominent examples are a flag in the wind, flutter of airplane wings, bridge excitations and collapses due to wind, and oscillating mooring cables and risers in offshore applications, just to name a few.

Thus, the single disciplines of fluid mechanics and structural analysis cannot be solved independently, like it is mostly preferred in “traditional engineering solution approaches”. The interaction causes additional phenomena which make it necessary to solve the whole coupled physical system of fluid field, structural field and the suitable coupling conditions at the interface between them. This complexity very often closes the evaluation of this multiphysics problem to well-established experimental approaches. Hence, the development and application of sophisticated numerical methods to evaluate these effects in nature and technical practice is necessary.

At the Chair of Structural Analysis, a modular partitioned solution approach is pursued which accommodates the interdisciplinary nature of this topic and facilitates respective cooperations between the Chair of Structural Analysis and other acknowledged experts in the field. As a consequence, big emphasis in research is on the development and implementation of efficient and robust algorithms for the solution of the coupling conditions and the treatment of non-matching grids at the fluid-structure interface. For the realization of the coupled simulations, an own coupling software called EMPIRE (Enhanced Multi-Physics Interface Research Engine) is continuously developed at the Chair of Structural Analysis which is kept generic, to enable also the simulation of more than two coupled fields via n-code coupling. Furthermore, the partitioned shape optimization of coupled problems is an ongoing topic of intense research which will extend the use of the developed methodologies to get in-depth insight of the coupled physical behavior to a mean which supports the design process e.g. with sensitivity evaluations.