## Adaptive reduced-order modeling for non-linear fluid-structure interaction

Thari, A., Pasquariello, V., Aage, N., Hickel, S. (2021) *Computers and Fluids* 229: 105099. doi: 10.1016/j.compfluid.2021.105099

We present an adaptive reduced-order model for the efficient time-resolved simulation of fluid–structure interaction problems with complex and non-linear deformations. The model is based on repeated linearizations of the structural balance equations. Upon each linearization step, the number of unknowns is strongly decreased by using modal reduction, which leads to a substantial gain in computational efficiency.

## A cut-cell finite volume-finite element coupling approach for fluid-structure interaction in compressible flow

Pasquariello, V., Hammerl, G., Örley, F., Hickel, S., Danowski, C., Popp, A., Wall, W.A., Adams, N.A. (2016) *Journal of Computational Physics* 307: 670-695. doi: 10.1016/j.jcp.2015.12.013

We present a loosely coupled approach for the solution of fluid–structure interaction problems between a compressible flow and a deformable structure. The method is based on staggered Dirichlet–Neumann partitioning. The interface motion in the Eulerian frame is accounted for by a conservative cut-cell Immersed Boundary method. The present approach enables sub-cell resolution by considering individual cut-elements within a single fluid cell, which guarantees an accurate representation of the time-varying solid interface.

## Cut-element based immersed boundary method for moving geometries in compressible liquid flows with cavitation

Örley, F., Pasquariello, V., Hickel, S., Adams, N.A. (2015) *Journal of Computational Physics* 283: 1-22. doi: 10.1016/j.jcp.2014.11.028

The conservative immersed interface method for representing complex immersed solid boundaries or phase interfaces on Cartesian grids is improved and extended to allow for the simulation of weakly compressible fluid flows through moving geometries. We demonstrate that an approximation of moving interfaces by a level-set field results in unphysical oscillations in the vicinity of sharp corners when dealing with weakly compressible fluids such as water. By introducing an exact reconstruction of the cut-cell properties directly based on a surface triangulation of the immersed boundary, we are able to recover the correct flow evolution free of numerical artifacts.

## An innovative approach to thermo-fluid-structure interaction based on an immersed interface method and a monolithic thermo-structure interaction algorithm

Grilli, M., Hickel, S., Adams, N.A., Hammerl, G., Danowski, C., Wall, W.A. (2012) * *

*AIAA paper*2012-3267. doi: 10.2514/6.2012-3267

We present a loosely-coupled approach for the solution of the thermo-fluid-structure interaction problem, based on Dirichlet-Neumann partitioning. A cartesian grid finite volume scheme, with conservative interface method is used for the fluid and a finite-element scheme for the thermo-structure problem. Special attention is given to the transfer of forces, temperatures and to the structural positions.