EPTT 2022

13th Spring School on Transition and Turbulence

Modal stability analysis of aeroelastic systems under galloping

Submission Author: Victor Peron , SP
Co-Authors: Victor Peron, Bruno Carmo, Daiane Iglesia Dolci
Presenter: Victor Peron

doi://10.26678/ABCM.EPTT2022.EPT22-0029

 

Abstract

This works aims at performing linear stability analysis of fluid-structure interactions systems, focusing on aeroelastic bodies subject to galloping. First, the physical phenomena behind the coupled instability are described, and the problem is set up to acknowledge the development of galloping in current fluid mechanic simulations. The computational limitations of the quasi-steady approach are discussed and endorsed in some of the mesh convergence decisions made. We take advantage of the moving frame of reference technique, allowing the rigid motion of the mesh, as well as the spectral\hp element discretization, to develop a solver that combines this high-order finite element method providing solutions with low numerical errors. We perform numerical nonlinear simulations of the flow around elastically mounted noncircular bluff bodies to investigate the behavior of the coupled system and evaluate the system response with the variation of flow parameters (such as Reynolds number) and structural parameters (such as mass ratio and reduced velocity). Next, the methodology for stability modal analysis of the coupled systems is defined, and numeric simulations are carried out to obtain complementary sets of the leading eigenvalues responsible for the magnitude and oscillatory responses of these systems. These eigenvalues are determined as the solution for the perturbed coupled Navier-Stokes and structural equations, presented in the form of direct modes. Then, with a complete set of parameters, responses and respective eigenvalues, the fluid-structure stability is discussed in terms of the flow and structure parameters and geometry. We provide bifurcation diagrams, as well as the direct flow fields for the evolution or decay of the perturbation energy in the system.

Keywords

fluid-structure interactions, Aeroelasticity, Aeroelastic Stability, spectral element method

 

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