转轴位置对俯仰动态特性的影响

Pivot Effects on pitching Dynamic Flow Behaviors

研究了转轴位置对机翼、机身和三个组合体上翼面的动态特性的影响。对于机翼和机身，当转轴位置后移时其动态迟滞效应更为强烈。当翼面处于转轴之前，上仰时会出现更为严重的动态迟滞效应，因此鸭翼达到动失速状态较晚。而当翼而处于转轴之后时，如尾翼，将会更早地出现动失速。转轴位置对动态迟滞特性的影响可以认为主要是由于俯仰运动时的动态洗流影响所导致的实际有效迎角的变化，由此影响了动态分离涡及其发展。

The pivot effects on dynamic hysteresis characteristics were studied by pitching wing, body and three kinds of wing-body combina- tions. Very important effects of the piyot positions on dynamics hyster-esis characteristics appeared. The dynamic hysteresis behaviors were serious as the pivot position moved backward on the wing. Also similar behaviors appeared on the body as the pivot position was far from the tip of body. Three kinds of wing body combinations were used for investiga- ting the pivot effect on the wings of the combinations. Much more serious dynamic hysteresis appeared on the wing ahead of the pivot and the dynamic stall occured on the canard later. Opposite hysteresis behaviors appeared on the wing behind of the pivot. It is supposed that the dyna- mic stall appeared on the tail early. The mechallism of the pivot effect on the dynamic hysteresis characteristics were probed mainly due to the dynamic wash effect during pitching up or down and changing local efficient angle of attack, which affected the dynamic vortices and their developing.