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

使用细长的、大后掠的机翼，一方面在亚音速和跨音速范围内实现高机动性，另一方面实现低超音速阻力，会导致一些问题，这些问题通常不是由于满足空气动力性能要求而引起的，而是与不希望有的稳定性和可控性特性有关的。 大迎角时的典型问题与上仰和侧滑引起的滚转力矩导数发散有关。在这种情况下，对于大迎角范围内的纵向和横向稳定性，可以有利地使用在双后掠或三后掠前缘处出现的多个涡流系统。因此，该项目旨在提高对具有交错前缘后掠的小展弦比机翼上多涡系流动物理特性的理解。与单后掠前缘脱落的前缘涡的大量数据库相比，在交错前缘后掠干扰涡系及其对气动特性和稳定性影响的研究和分析方面存在着很大的差距。将详细分析与多涡系有关的干扰和合并前缘涡的分离和涡拓扑结构，并根据前缘后掠角、下游距离、俯仰角和侧滑角表征干扰和合并。此外，还将研究干扰涡对涡破裂的影响，以评估在何种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。在第二个资助期内，研究集中在圆形前缘涡演化情况下的干扰涡系上，特别是在高亚音速马赫数范围内的干扰涡系上，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.