Aeroelastic Analysis Of All-movable Control Surface In Subsonic Speed

An issue related to the flutter and its catastrophic/benign character represented by Limit Cycle Oscillation(LCO)of all-movable control surface,as well to their control is addressed in the present work.To the approach of this issue:(1)Quasi-Steady(QS)theory and Computational Fluid Dynamics(CFD)of subsonic flow are implemented,(2)Equations of motion of a two-dimensional typical section with cubic nonlinear stiffness in the pitching direction are established,(3)Uncoupled bending/torsion frequencies of the selected control surface are computed using recently developed Transfer Matrix Method of Multibody System Dynamics(MSTMM),and(4)A powerful methodology based on the Lyapunov First Quantity(LFQ)is carried out to study the bifurcation behavior of the aeroelastic system in the vicinity of the flutter boundary.The main objectives of this study are to analyze the implications of structural nonlinearities on the character of the flutter instability boundary of the control surface section,and to implement a control capability enabling one to control both the flutter boundary and its character.By this way,it may expand the operational envelope without the occurrence of catastrophic failures.To verify the accuracy of the present work,comparisons are made for(a)Uncoupled natural frequencies between the proposal MSTMM and ANSYS software,and(b)Lift force coefficient between CFD FLUENT software and experimental data.Close agreements are obtained within 5%for both comparisons.Via LFQ,a general picture of the variation of catastrophic and benign parts of the flutter boundary as a function of structure nonlinearity and of the parameters characterizing the aeroelastic model can be obtained.In addition,the potential of active linear and nonlinear control issue is highlighted and increase the flutter speed and convert the dangerous boundary to the safe one.