Aerodynamics of interfering vortex systems at low aspect ratio wings with multiple swept leading-edge

使用细长的、高度后掠的机翼一方面在亚音速和跨音速区域实现高机动性，另一方面在低超音速阻力区域实现高机动性，可能会导致一些问题，这些问题通常不是由气动性能要求的实现引起的，而是与不期望的稳定性和可控性特性相关。大迎角下的典型问题是俯仰和侧滑引起的滚转力矩导数散度问题。在这种情况下，出现在双掠或三掠前缘的多涡系统可以在大攻角范围内的纵向和横向稳定性方面得到有利的利用。因此，该项目旨在提高对低展弦比交错前缘掠翼下多涡系统流动物理的理解。与单掠前缘涡的庞大数据库相比，对交错掠前缘干扰涡系统及其对气动性能和稳定性的影响的研究和分析还存在很大的空白。详细分析了与多涡系统相关的前缘涡干涉和合并相关的分离和涡拓扑结构，并根据前缘掠度、下游距离、俯距和侧滑角对干涉和合并进行了表征。此外，还研究了干涉涡对旋涡破裂的影响，以评估在多大程度上可以实现涡流的稳定，从而改善飞行控制和减少抖振现象。在第二个资助期，研究重点是在圆前缘涡演化情况下的干涉涡系统，特别是在高亚音速马赫数范围内的干涉涡系统，其中激波-涡相互作用占主导地位。

Using slender, highly swept wings to achieve high maneuverability in the subsonic and transonic regime on the one hand and low supersonic drag on the other hand can lead to problems that usually do not result from the fulfillment of aerodynamic performance requirements, but are associated with undesirable stability and controllability characteristics. Typical problems at higher angles of attack are related to pitch-up and the divergence in the rolling moment derivative due to sideslip. In this context, multiple vortex systems, which occur at double or triple swept leading edges, can advantageously be used with regard to longitudinal and lateral stability in the high angle of attack range. The project therefore aims at an improved understanding of the flow physics of multiple vortex systems at low aspect ratio wings with staggered leading edge sweep. In contrast to the large data base for leading edge vortices shed at a single swept leading edge, there is a significant gap in the investigation and analysis of interfering vortex systems at staggered leading edge sweep and their impact on aerodynamic properties and stability characteristics. The separation and vortex topologies related to interfering and merging leading-edge vortices associated with multiple vortex systems will be analyzed in detail and the interference and merging will be characterized depending on leading edge sweep, downstream distance, pitch and sideslip angle. Furthermore, the influence of the interfering vortices on vortex bursting is to be investigated in order to assess to which extent a stabilization of the vortical flow can be achieved, which leads to improved flight control and reduction of buffeting phenomena. For the second funding period, the investigations concentrate on interfering vortex systems in the case of vortex evolution at round leading edges and, in particular, on interfering vortex systems in the high subsonic Mach number range, in which shock-vortex interactions dominate.