Numerical simulation on gust response of elastic wing

The numerical method to calculate the gust response of elastic wing was developed in this paper. In this numerical method, the aerodynamic forces of the rectangular wing with aspect ratio of 5 were calculated by solving the unsteady Euler equations, the elastic effect was considered with Rayleigh-Ritz method, so that the fluid dynamic and structural dynamic problems can be coupled to solve. In order to validate the feasibility of this numerical method, the case of gust leading a step change of the rigid wing's incidence and the case of Limiting Cycle Oscillation calculation of NLR7301 airfoil were investigated. The calculated results of these cases agreed with those presented in references and therefore verified the effectiveness of the numerical method. Furthermore, the elastic effect was taken in account, and at first only the first three fundamental elastic modes were used to calculate the wing's response of 1-cos gust. It can be seen from the result that the peak value of lift response calculated by elastic wing was lower than that calculated with rigid wing, which agreed with the result in the reference. Finally, a high-order elastic mode was employed in the calculation and the results revealed that there was an agreement between the trends of the calculated curves of aerodynamic forces and those calculated only involving the first three fundamental elastic modes. However, there were some high-frequency oscillations in the aerodynamic forces due to the employment of high-order elastic mode and the oscillation frequency should be consistent with the natural frequency of the high-order elastic mode.