Limit Cycle Oscillation Prediction via Support Vector Machine Based Reduced Order Model

Author(s):  
Gang Chen ◽  
Yueming Li ◽  
Zuo Yingtao ◽  
Sun Jian ◽  
Patrick Hu
2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Gang Chen ◽  
Yingtao Zuo ◽  
Jian Sun ◽  
Yueming Li

It is not easy for the system identification-based reduced-order model (ROM) and even eigenmode based reduced-order model to predict the limit cycle oscillation generated by the nonlinear unsteady aerodynamics. Most of these traditional ROMs are sensitive to the flow parameter variation. In order to deal with this problem, a support vector machine- (SVM-) based ROM was investigated and the general construction framework was proposed. The two-DOF aeroelastic system for the NACA 64A010 airfoil in transonic flow was then demonstrated for the new SVM-based ROM. The simulation results show that the new ROM can capture the LCO behavior of the nonlinear aeroelastic system with good accuracy and high efficiency. The robustness and computational efficiency of the SVM-based ROM would provide a promising tool for real-time flight simulation including nonlinear aeroelastic effects.


2011 ◽  
Vol 08 (01) ◽  
pp. 77-90 ◽  
Author(s):  
GANG CHEN ◽  
YUE-MING LI ◽  
GUI-RONG YAN

When the amplitude of the oscillation of the unsteady flow is large or there is large perturbation relative to the mean background flow, the traditional proper orthogonal decomposition/reduced order model (POD/ROM) based on linearized time or frequency domain small disturbance solvers cannot capture the main nonlinear features well such as limit cycle oscillation (LCO), which is very dangerous for the structure. Therefore, the traditional linear ROMs are not good enough for limit cycles prediction and active control law design. A new nonlinear ROM based on dynamically nonlinear flow equation NPOD/ROM was investigated. The nonlinear second-order snapshot equation in time domain for POD basis construction is obtained from the Taylor series expansion of the flow solver. The simulation results indicate that the NPOD/ROM can capture LCO very well and is also very convenient for active control law design, while the traditional POD/ROM lose effectiveness.


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