Numerical FSI investigation based on LES: Flow past a cylinder with a flexible splitter plate involving large deformations (FSI-PfS-2a)

The objective of this paper is to provide a detailed numerical investigation on the fluid–structure interaction (FSI) test case presented in Kalmbach and Breuer (J. of Fluids and Structures, 42, (2013), 369–387). It relies on detailed experimental investigations on the fluid flow and the structure deformation using modern optical measurement techniques such as particle-image velocimetry and laser triangulation sensors. The present numerical study is based on an efficient partitioned FSI coupling scheme especially developed for turbulent flow simulations around light-weight structures using large-eddy simulation. The current FSI configuration is composed of a fixed cylinder with a flexible thin rubber plate and a rear mass inducing a turbulent flow (Re = 30,470). Mainly based on a movement-induced excitation the flexible structure oscillates in the second swiveling mode involving large deformations. Thus, particular attention has been paid to the computational model and the numerical set-up. Special seven-parameters shell elements are applied to precisely model the flexible structure. Structural tests are carried out to approximate the optimal structural parameters. A fine and smooth fluid mesh has been generated in order to correctly predict the wide range of different flow structures presents near and behind the flexible rubber plate. A phase-averaging is applied to the numerical results obtained, so that they can be compared with the phase-averaged experimental data. Both are found to be in close agreement exhibiting a structure deformation in the second swiveling mode with similar frequencies and amplitudes. Finally, a sensitivity study is carried out to show the influence of different physical parameters (e.g. Young’s modulus) and modeling aspects (e.g. subgrid-scale model) on the FSI phenomenon.