Pitching dynamic stability is significant for the aerodynamic performance of an aircraft at a large angle of attack (AoA). Commonly, the dynamic behaviour of vortex breakdown flows over an aircraft with a delta or double-delta wing (DW or DDW) configuration is closely related to the pitching dynamic stability. An 80°/65° DDW subjected to sinusoidal pitching motions around the stall AoA was numerically investigated using the delayed detached eddy simulation method [1]. This study is focused on the correlation between the unsteady behaviour of the vortex burst point (BP) and pitching dynamic stability. The reverse of the pitching dynamic stability is closely related to the inconsistent movement of the BP during the upstroke and downstroke in one pitching period. When the upstream speed of the BP is higher than the downstream speed, the variation in the pitching moment is ahead of the AoA, which leads to dynamic instability. Conversely, when the downstream speed is higher than the upstream speed, the DDW is dynamically stable. This correlation can be interpreted through the energy transfer relationship between the vortex breakdown flows and DDW model.

俯仰动态稳定性对于飞机在大迎角（AoA）时的空气动力学性能至关重要。通常，涡旋破坏流在具有三角翼或双三角翼（DW或DDW）构型的飞机上的动态行为与俯仰动态稳定性密切相关。使用延迟分离涡模拟方法[1]对80°/ 65°DDW绕失速AoA进行正弦俯仰运动进行了数值研究。这项研究的重点是涡流爆发点（BP）的非稳态行为与俯仰动力稳定性之间的相关性。俯仰动态稳定性的倒转与一个俯仰周期中的上冲程和下冲程期间BP的不一致运动密切相关。当BP的上游速度高于下游速度时，俯仰力矩的变化在AoA之前，这会导致动态不稳定。相反，当下游速度高于上游速度时，DDW是动态稳定的。这种相关性可以通过涡旋破裂流与DDW模型之间的能量传递关系来解释。