Fluid-structure interaction in turbulent flows and the influence of LES subgrid-scale models

Abstract

The combination of fluid-structure interaction (FSI) and turbulent flows is a matter of particular interest in many fields of technical applications. Partitioned coupling schemes enable the coupling of flow solvers which for example have been especially developed for the computation of turbulent flows with highly adapted algorithms for the computation of the structure field. Here, the turbulent flow field around a structure with a rotatory degree of freedom is computed by the use of Large-Eddy Simulation (LES) which relies on subgrid-scale models (SGS) to account for the impact of the small unresolved scales on the larger scales of the flow field. In computational fluid dynamics subgrid-scale modeling is an issue of concern since the seventies of the last century focusing on pure flow problems like free streams, channel flows or flows around fixed structures like cylinders. In this contribution the actual results of still ongoing investigations on the impact of subgrid-scale models on FSI computations are shown. In detail the turbulent flow at Re = 23,423 around a cylinder with an attached beam is considered. The rigid structure is enabled to rotate around the center of the cylinder. The subgrid-scale model of Smagorinsky (1963), the WALE model (1998) and the dynamic model of Germano et al. (1991) with modifications by Lilly (1992) are considered. Furthermore, for the Smagorinsky and the WALE model variations of the model constants are taken into account and their influence on the results is evaluated.