绕三角翼纵向俯仰大迎角气动特性计算研究

 采用数值计算方法, 对三角翼从0°上仰至90°的动态流场结构进行了计算, 在此基础上, 对三角翼在上仰过程中受到横侧小扰动情况下的流场结构和气动力特性进行了计算研究。给出了三角翼纵向动态情况下的气动力系数变化, 特别是大迎角横侧力矩系数的变化特征, 并对受到横侧小扰动后横侧运动的稳定性进行了计算与分析。结果表明, 机翼的上仰运动延迟了机翼上翼面旋涡的破裂。同时, 随着机翼俯仰角速度的提高, 机翼抵抗旋涡非对称破裂的能力明显增强, 机翼运动的稳定性也明显提高。

Numerical Investigation of Unsteady Aerodynamic Characteristics of Pitching Delta Wings

A numer ical investigation of the structure of the vortical flowfield over a delta w ing w hen undergoing aPitch-up motion from 0 to 90 is presented her e. Three-dimensional Navier-Strokes numerical simulations were carried out to predict the complex leeward-side flow field char acterist ics that are dominated by the effect of the breakdown of the leading-edge vort ices. Tw o cases are considered to investig ate the frequency effect on the flow field structure and aer odynamic lo ads for the delta w ing . The later al moments are more evident as the frequency decr eases.Pitching motion w ith hig h frequency delays t he vortex br eakdow n. Besides, the influences of a tr ansient lateral disturbance on the later al aerodynamics are resear ched. For low er fr equency case, the later al moment diverges even ift he disturbance occurs at an angle of attack at which the vortex do not breakdown over the wing . As the frequencyincreases, the lateral moment has no evident chang e after the transient lateral disturbance occurs, and t he lateral-directional stability is more pro nounced.