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In this paper, we introduce a new nonlocal modal hydrodynamic theory for fluid–structure interactions (FSI) of light, flexible cantilever beams and plates undergoing small amplitude vibrations in Newtonian, incompressible, viscous, heavy fluids otherwise at rest. For low aspect ratio flexible structures and high mode numbers, three dimensional (3D) and nonlocal fluid effects become prominent drivers of the coupled dynamics, to the point that existing local hydrodynamic theories based on two dimensional (2D) fluid approximations become inadequate to predict the system response. On the other hand, our approach is based on a rigorous, yet efficient, 3D treatment of the hydrodynamic loading on cantilevered thin structures. The off-line solution of the FSI problem results in the so-called nonlocal modal hydrodynamic function matrix, that is, the representation of the nonlocal hydrodynamic load operator on a basis formed by the structural modes. Our theory then integrates the nonlocal hydrodynamics within a fully coupled structural modal model in the frequency domain. We compare and discuss our theory predictions in terms of frequency response functions, mode shapes, hydrodynamic loads, quality factors, added mass ratios with the predictions of the classical local approaches, for different actuation scenarios, identifying the limitations of the hypotheses underlying existing treatments. Importantly, we also validate our new model with experiments conducted on flexible square plates. While computationally efficient, our fully coupled theory is exact up to numerical truncation and can bridge knowledge gaps in the design and analysis of FSI systems based on low aspect ratio flexible beams and plates. [ABSTRACT FROM AUTHOR]

Abstract: The paper is concerned with an efficient partitioned coupling scheme developed for dynamic fluid–structure interaction problems in turbulent flows predicted by eddy-resolving schemes such as large-eddy simulation (LES). To account for the added-mass effect for high density ratios of the fluid to the structure, the semi-implicit scheme guarantees strong coupling among flow and structure, but also maintains the advantageous properties of explicit time-marching schemes often used for turbulence simulations. Thus by coupling an advanced LES code for the turbulent fluid flow with a code especially suited for the prediction of shells and membranes, an appropriate tool for the time-resolved prediction of instantaneous turbulent flows around light, thin-walled structures results. Based on an established benchmark case in laminar flow, i.e., the flow around a cylinder with an attached flexible structure at the backside, the entire methodology is analyzed thoroughly including a grid independence study. After this validation, the benchmark case is finally extended to the turbulent flow regime and predicted as a coupled FSI problem applying the newly developed scheme based on a predictor–corrector method. The entire methodology is found to be stable and robust. The turbulent flow field around the flexible structure and the deflection of the structure itself are analyzed in detail. [Copyright &y& Elsevier]