Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
SIMULATION OF AIRFOIL MODEL WITH TWO DEGREES OF FREEDOM AND FLUTTER ANALYSIS BASED ON STEADY AND QUASISTEADY THEORIES
Submission Author:
Gabriel Vicentin Pereira Lapa , SP
Co-Authors:
Gabriel Vicentin Pereira Lapa, Alfredo Gay Neto, Guilherme Franzini
Presenter: Gabriel Vicentin Pereira Lapa
doi://10.26678/ABCM.COBEM2021.COB2021-0102
Abstract
Flutter instability of an airfoil is characterized by coupling between two vibration modes, initially with close natural frequencies. When changing the free-stream velocity, the associated natural frequencies with such modes are changed. Therefore, depending on this velocity, the motion behaves with growing amplitude and, in practice, it represents the disruption of the airfoil structure. This paper aims to study the conditions for this growing-amplitude motion as well as to study the associated wind speed as a system parameter for which flutter takes place. The study is split into two parts: the first one is based on an analysis of the coupling of the natural frequency modes due to the incidence of the wind, thus the beginning of the flutter effect. An alternative way for finding the wind speed associated with flutter is via the Lyapunov’s indirect method, considering the steady and quasi-steady aerodynamic theories. In the second part, a numerical time-integration simulation for an airfoil model was carried out considering steady and quasi-steady theories. The results were compared with other tools, with good agreement. Several analyzes were made for different wind speeds. All of them presented results coincident with Lyapunov’s indirect method for their respective aerodynamics theories. The lag between the displacement and angular movement was 180º in all aerodynamics theories.
Keywords
Flutter, Lyapunov’s method, steady and quasi-steady theories
