中文摘要：

为研究柔性变后掠飞行器变形过程中的非定常气动力,对柔性变后掠飞行器进行了非定常数值仿真。首先分析了柔性变后掠飞行器在特定后掠角下的定常气动特性,接着选用三种变后掠周期进行了非定常计算,分析了不同变后掠速度对飞行器气动特性的影响,以及定常与非定常气动特性的差别,并研究了这种差异产生的原因。结果表明:柔性变后掠飞行器通过后掠角的改变可以使实时气动性能达到最优;不同变后掠速度引起的气动力差异不大;定常气动力与非定常气动力最大差异不超过7%,其差异主要是由于机翼上气动力的差异引起;非定常计算的升力、阻力系数大于定常结果,俯仰力矩系数与定常计算值差异不大。非定常气动力的产生机理是由于机翼的附加速度所引起的,与流场迟滞无关。总体上看,攻角小于14°时,小后掠可以取得较大的升力、阻力系数;大于14°攻角,大后掠的升力、阻力系数较大;所有后掠角均在4°攻角处取得最大升阻比且小后掠角的升阻比较大;当升力系数小于1.28时,小后掠角产生较小的阻力系数,超过这一数值,大后掠角的阻力系数较小。

英文摘要：

In order to investigate the unsteady aerodynamic performance of flexible variable-sweep morphing aircraft during deformation process,an unsteady numerical simulation is pro-posed.The steady aerodynamic characteristics of flexible variable-sweep morphing aircraft in spe-cific sweep angle are analyzed firstly.After that,three different variable sweep periods are select-ed to fulfill the unsteady numerical simulation.The impact on the aerodynamic characteristics of variable-sweep morphing aircraft is analyzed for different variable-sweep speeds.The difference of steady and unsteady aerodynamic characteristics is also analyzed,and the reason of this differ-ence is investigated.The result demonstrates that:the real-time aerodynamic performance of flexible variable-sweep morphing aircraft can be optimized through sweep changes;the aerody-namic force difference in different variable sweep speeds is not very obvious;the difference be-tween steady and unsteady aerodynamic force mainly caused by the wing is no more than 7% at the angle of attack 2°,and the horizontal tail’s contribution can be neglected.The lift and drag coefficients of unsteady numerical simulation are larger than that of the steady numerical simula-tion,and the difference of pitching coefficients can be neglected also.In general,the lift and drag coefficients are larger at the low sweep angle when the angle of attack is smaller than 14°.The lift and drag coefficients are larger at the high sweep angle,when the angle of attack is bigger than that degree.The lift-drag ratio will reach to the maximum at the angle of attack 4°,and the lift-drag radio is larger at the small sweep angle.When the lift coefficient is smaller than 1.28 and the sweep is very small,the drag coefficient of the model is smaller,otherwise the drag is larger at the high sweep.Mechanism for the unsteady aerodynamic force is caused by wing addi-tional-velocity and has nothing to do with flow field hysteresis.