RANDOM BIFURCATION AND POWER SPECTRUM ANALYSIS OF A 2-DOF AIRFOIL WITH FREEPLAY NONLINEAR IN PITCH
ZHAO Demin, ZHANG Qichang, WANG Wei
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Department of Mechanical Engineering, Tianjin University. Tianjin 300072. China
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History+
Received
Revised
Published
2008-10-15
1900-01-01
2009-06-25
Issue Date
2009-06-25
Abstract
The 2-DOF airfoil system with freeplay nonlinearity in pitch, excited by longitudinal and vertical random turbulence, is investigated numerically. The random bifurcation including P-and D-bifurcation is studies in term of the Bi-dimension probability density function (PDF) and the largest Lyapunov exponent respectively. The power spectral density function is also obtained in the paper. The results show in two different aspects. First when the airspeed lies in pre- and post-flutter speeds regime, the shapes of the Bi-dimension PDFs change as the turbulence intensity change from low to high, which demonstrates that the P-bifurcation has happened at the both airspeeds regimes. However, the largest Lyapunov exponents show that the D-bifurcation has not happened in whatever pre- and post-flutter speeds regime regardless when the turbulence intensity is low or high. Second the power spectral density functions are obtained in different airspeed regimes, the conclusion presents that when the airfoil flutter occur, the more power of the system focus on the flutter frequency.
ZHAO Demin;ZHANG Qichang;WANG Wei.
RANDOM BIFURCATION AND POWER SPECTRUM ANALYSIS OF A 2-DOF AIRFOIL WITH FREEPLAY NONLINEAR IN PITCH[J]. Journal of Vibration and Shock, 2009, 28(6): 86-89
