Numerical Simulation of Fluid–Structure Interaction Using Eddy–Resolving Schemes

Eddy–resolving schemes such as large–eddy simulation (LES) or detached-eddy simulation (DES) have become popular due to their favorable capabilities of predicting complex turbulent flows. That is especially true for instantaneous flow processes involving large–scale flow structures such as separation, reattachment and vortex shedding. Flow phenomena of such kind are very often encountered when the flow around or through a device enforces the structures to be deformed or displaced, i.e. for fluid–structure interaction (FSI). The present study deals with several aspects which have to be taken into account when LES is married to FSI. That comprises the coupling scheme, the handling of moving or deformable grids and the question how their quality requirements can be achieved. A coupling scheme leading to strong coupling among flow and structure, but also maintaining the advantageous properties of explicit time–marching schemes used for LES, was set up and analyzed. Thus a new and favorable coupling procedure for FSI within the LES context was developed. This and other issues of the numerical methods applied such as the measures to maintain the grid quality are discussed in detail. Results of validation test cases of FSI in the context of rigid body motions (e.g. an elastically mounted cylinder or a swiveling flat plate) as well as benchmark results with flexible structures computed with a finite–element code are presented.