Numerical investigation of transient response of a coupled two-degrees-of-freedom symmetric airfoil before flutter

Abstract

In this study, the numerical investigation of free dynamic response of a rigid, symmetric airfoil having two coupled degrees of freedom is performed. The airfoil is excited using two different mechanisms. Firstly, a mechanical excitation scenario is simulated using initial conditions for both the degrees of freedom. Dynamic airfoil response in terms of amplitudes of oscillation is recorded under no flow as well as uniform upstream flow conditions. In the second scenario, an upstream flow perturbation is introduced in the form of a gust superimposed on the otherwise uniform in-flow. Transient energy amplification behavior of the airfoil under both scenarios is monitored. The findings are presented in terms of dimensionless aerodynamic coefficients, oscillations amplitudes, and total energy of the airfoil. Detailed comparisons of the experimental data and results obtained using analytical models are developed and discussed using a very simple simulation methodology.