محاسبه دامنه و فرکانس نوسانات سیکل محدود ایرفویل با اثر غیرخطی درجه۳

Abstract

In this paper governing aeroelastic equations of the two degree of freedom airfoil containing cubic nonlinearity in an incompressible flow are presented in the both time and frequency domains. Numerical solution and harmonic balance methods are applied for the solution of govening aeroelastic equations in the time domain to obtain amplitude and frequency of limit cycle oscillations (LCO). Also, describing function method is modified and presented for the pediction of the LCO amplitude and frequency in the frequency domain. LCO frequency and amplitude are obtained via applying three methods as harmonic balance, describing function and numerical solution methods for two different cases. Comparision between the results of these three methods shows a very good agreement.