Fluid-Structure Interaction; Stiffness Effects on Airfoil Flutter: A numerical study of airfoil flutter in STAR-CCM+

Abstract

This report looks in to the phenomenon called flutter, a type of flow induced vibration in structures occurring at specific flow conditions. Specifically, the project looks at how flutter affects airfoils, and how the structural stiffness of the airfoil impacts the flutter effects at a certain set of conditions. The analysis was carried out using commercial CFD solver STAR-CCM+. Within this software, the structural dynamics of a symmetric NACA0012 airfoil were modeled as a two-degree-of-freedom system with one bending mode and one torsional mode. Due to constraints on computational power and time, the mesh generation was adjusted to reduce computational time as much as possible without it effecting the behaviour of certain parameters, particularly the aerodynamic lift coefficient which was considered an important performance measure for the airfoil. The results indicate that with a given set of operating conditions, adjusting the structural stiffness can be used as an effective countermeasure against flutter. However due to the mesh limitations mentioned above, the quality of the results can be questioned when looking closer at the flow field and numerical instabilities effecting some parameters.