| Summary: | 碩士 === 國立中興大學 === 機械工程學系 === 94 === The aerodynamics and stealth often conflict each other in designing the stealth aircraft shape. In this research, we study the static and dynamic behaviors at high angle of attack of UCAV by water tunnel experiment. In order to investigate the burst vortex position, we use parameters including pitch angles, sideslipe angles, action pitch rate in pitch up and pitch down process. The experiment results show that model W type empennage has irregular vortex not only for the model. It also leads to an early burst position and other tail vortex to form backflow effect. This effect will lead to a split form of airframe vortex. In static state, burst vortex points move toward the front side of wing when the angle of attack of UCAV increases. In the dynamic state of UCAV model, the right and left burst vortex position are both delayed with unstable rocking at zero sideslip angle.
Investigation results show that while increase the pitch-up rate, the maximum lift-up coefficient and stall angle of attack will increase. During the process of pitch down, the reduction of pitch rate will decrease lift-up coefficients and stall angle. Different pitch rates affect other aerodynamic coefficient, and the control of plane simultaneously.
|
|---|
