Experimental analysis of shock oscillations during shock-boundary layer interaction in transonic flow with artificially introduced sound waves

人工引入声波跨音速流激波-边界层相互作用过程中激波振荡的实验分析

• 批准号: 348033788
• 负责人: Dr.-Ing. Michael Klaas
• 金额: --
• 依托单位: Lehrstuhl für Strömungslehre und Aerodynamisches Institut (AIA)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/348033788?language=en
• 关键词: Experimental; analysis; shock; oscillations; during

The mechanisms that lead to self-sustained shockwave oscillations in the transonic flow around airfoils are not fully understood, yet. The initially steady flow becomes unstable and induces variations in drag and in lift. This phenomenon, also known as buffet, can lead to a critical state for the wing structure of an airfoil. Therefore, regarding the increasing importance of virtual flight test and weight optimization of supporting structures, it is of outstanding importance to reach a better predictability of the disturbances in the flow field that lead to buffet. However, several and to some extent contradictory theories concerning the physical mechanisms underlying buffet can be found in literature. Hence, the global objective of this experimental study is to gain insight into the mechanisms that cause and maintain buffet, following the hypothesis that it is the trailing-edge noise that leads to the unsteadiness. For this, the transonic flow field around a supercritical, two-dimensional airfoil is analyzed using high-speed tomographic Particle-Image Velocimetry and unsteady pressure measurements. To determine the impact of the sound waves and of the interaction between shock position, boundary layer, free shear layer, and acoustic field, sound waves of specific properties are artificially introduced into the flow field, and the sound field naturally generated at the trailing edge is manipulated by introducing a porous trailing edge. Whereas the flow filed around the airfoil with the non-porous trailing edge shows self-sustained shock oscillations, it is expected that the flow field does not exhibit any shock oscillations when the sound field is manipulated by a porous trailing edge. Subsequently, it will be analyzed whether or not buffet can be reinitiated by the artificial introduction of sound waves. By investigating the two trailing-edge configurations, the impact of the acoustic disturbances originating at the trailing edge on the buffet phenomenon can be clarified. Hence, these fundamental investigations aim at demonstrating the need for the development of low-noise trailing edges, not only concerning the high-lift performance but also concerning the transonic flow regime.

在翼型跨音速绕流中引起自持激波振荡的机理还没有完全弄清楚。最初的定常流动变得不稳定，并引起阻力和升力的变化.这种现象，也被称为抖振，可导致机翼结构的临界状态。因此，考虑到虚拟飞行试验和支撑结构重量优化的重要性，获得流场中导致抖振的扰动的更好的可预测性是非常重要的。然而，在文献中可以找到几个和在某种程度上相互矛盾的理论，关于抖振的物理机制。因此，本实验研究的总体目标是深入了解引起和维持抖振的机制，假设是后缘噪声导致不稳定。为此，超临界，二维翼型的跨音速流场分析使用高速层析粒子图像测速仪和非定常压力测量。为了确定声波的影响以及激波位置、边界层、自由剪切层和声场之间的相互作用，将特定属性的声波人工引入流场，并通过引入多孔后缘来操纵在后缘处自然产生的声场。然而，在具有无孔后缘的翼型周围的流场显示出自持激波振荡，预计当声场由多孔后缘操纵时，流场不会表现出任何激波振荡。随后，将分析是否可以通过人工引入声波来重新引发抖振。通过对两种后缘构型的研究，可以明确后缘处产生的声扰动对抖振现象的影响。因此，这些基本研究的目的是证明发展低噪声后缘的必要性，这不仅关系到高升力性能，而且关系到跨音速流态。

项目成果

Detection of small-scale/large-scale interactions in turbulent wall-bounded flows

• DOI: 10.1103/physrevfluids.5.114610
• 发表时间: 2020-11
• 作者: E. Mäteling;M. Klaas;W. Schröder

Study on Large-Scale Amplitude Modulation of Near-Wall Small-Scale Structures in Turbulent Wall-Bounded Flows

• DOI: 10.1007/978-3-030-79561-0_7
• 发表时间: 2020-11
• 期刊: Notes on Numerical Fluid Mechanics and Multidisciplinary Design
• 作者: E. Mäteling;M. Klaas;W. Schröder

Investigation of shock–acoustic-wave interaction in transonic flow

跨音速流中冲击声波相互作用的研究

• DOI: 10.1007/s00348-017-2466-z
• 发表时间: 2018
• 期刊: Experiments in Fluids
• 影响因子: 2.4
• 作者: A. Feldhusen-Hoffmann;V. Statnikov;M. Klaas;W. Schröder
• 通讯作者: W. Schröder

Analysis of transonic buffet using dynamic mode decomposition

• DOI: 10.1007/s00348-020-03111-5
• 发表时间: 2021-03
• 期刊: Experiments in Fluids
• 影响因子: 2.4
• 作者: A. Feldhusen-Hoffmann;C. Lagemann;S. Loosen;P. Meysonnat;M. Klaas;W. Schröder