HIGHER ORDER SPECTRAL ANALYSIS OF ADDED MASS FORCES ON PLUNGING AIRFOIL AT HIGH FREQUENCIES
Mohamed Y. Zakaria1; Daniel A. Pereira2; Flavio D. Marques2; Muhammad R. Hajj1
1 virginia Tech; 2 University of São Paulo
doi:10.20906/CPS/COB-2015-0794
Resumo
Experiments are conducted on a NACA 0012 airfoil undergoing plunging oscillations at high frequency and different angles of attack. At extensively high oscillatory frequency and angles of attack, the formulation of the total loads responsible for generating nonconvensional lift mechanisms is very difficult to be modeled. Also, extracting the pure aerodynamic loads from the combined measured output signal (inertia, apparent mass and the aerodynamic circulatory forces) is a harsh task to do. As such, we introduce a dynamic model based on the gain response function to build an added mass model (response force function model with zero undisturbed flow) based on the obtained experimental data. Using the frequency domain through spectral analysis, we construct a response function gain assuming input-output dynamical system. We also use the higher order spectral analysis to investigate the higher-order interactions between the system frequencies which may leads to unconventional lift mechanisms at high operating frequencies and high angles of attack.
Palavras-chave: higher-order spectral analysis; high angle of attack; unsteady aerodynamics; Added mass