탄성변형과 비정상유동을 고려한 헬리콥터 동적모사에 관한 연구

Abstract

This dissertation describes the study of a coupled rotor-fuselage flight dynamic simulation that includes the effects of flexible blade and unsteady aerodynamics on flight dynamics characteristics of an articulated rotor helicopter. A new trim procedure is presented for the purpose of reducing potentially prohibitive computational requirements. Computational results are presented for trim solution, frequency response and time response to pilot inputs. It is verified by comparing the correlations with actual flight test data and commercial code(FLIGHTLAB) results. The results indicate that when an unsteady aerodynamic model is used, we can get improvements of solution in the trim pitch settings of main and tail rotor, in the frequency response, and the free flight response to pilot inputs. These changes slightly improve the correlation with flight test data, and can usually be explained by specific changes in lift distribution over the rotor disk. Noticeable changes can be seen in the poles associated with rotor modes. The effect is typically that of decreasing the damping, although no mode becomes unstable or dangerously lightly damped.