耦合运动非定常气动模型对飞机飞行特性仿真的影响

Effects of Coupled Motion Unsteady Aerodynamic Model on Flight Characteristics Simulation of Aircraft

在大振幅偏航滚转单自由度强迫振荡和耦合强迫振荡运动风洞试验的基础上,分别运用准定常气动力建模方法和非定常气动力建模方法,获取飞机的气动力模型;运用两种不同的气动力模型,对飞机的纵向正弦振荡机动飞行进行了仿真。结果表明,准定常模型在小迎角下的仿真结果与非定常模型的结果基本一致;在较大迎角时,准定常模型仿真结果趋于稳定,而非定常模型仿真结果使飞机进入横航向振荡飞行状态,这一现象与F-16XL的试飞结果类似,其主要原因是耦合运动的非定常模型与准定常模型所产生的阻尼特性不一致。这也表明,分析大迎角飞行特性时应考虑耦合运动下的非定常气动特性。

The quasi-steady aerodynamic model and unsteady aerodynamic model of an aircraft are established, based on wind tunnel test results of large-amplitude yawing-motion force oscillation, rolling motion force oscil lation and yawing rolling coupled-motion force oscillation. Using these models, the longitudinal dynamic responses are calculated with the oscillating control inputs. The simulation results show that, the dynamic re sponses of quasi steady model and unsteady model are coincidence basically at low angle of attack; but, at high angle of attack, the lateral-directional dynamic responses of quasi-steady model are stable, while the lateral-directional characteristics of unsteady model are oscillating. This phenomenon is similar with the flight test results of F-16XL. The main reason is that the damping characteristics of coupled-motion unsteady model and quasi steady model are different. These also show that the coupled-motion unsteady aerodynamic model is needed in flight characteristic simulation at high angle of attack.