Using the Discrete Vortex Method to Simulate the Stall Flutter Phenomenon

The Discrete Vortex Method (DVM) has been recently used by several researchers
in order to simulate the dynamic stall phenomenon on 2D airfoils oscillating at high angles of
attack or undergoing stall flutter oscillations. The aim of the present work is to investigate
whether such simulations are representative of the true physics governing such oscillation. A
DVM method is described and implemented. A basic validation of the method is performed
on the case of an impulsively started static airfoil at a low angle of attack. It is shown that the
steady state lift value obtained from the DVM method agrees with experimental
measurements. Subsequently, a DVM simulation is performed for the case of a NACA 0012
airfoil undergoing symmetric stall flutter oscillations. The simulation results are compared to
experimental results. It is shown that, while the general shape of the simulated lift variation
with time agrees with the experiment, there are significant mean value and phase differences
between experiment and simulation. Several justifications are suggested and improvements to
the DVM simulation proposed.