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.

尚不完全了解导致跨气管周围跨多气流中自我维持的冲击波振荡的机制。最初的稳定流量变得不稳定，并引起阻力和升力的变化。这种现象（也称为自助餐）可以导致机翼翼结构的临界状态。因此，关于虚拟飞行测试和支持结构的重量优化的重要性，可以更好地预测导致自助餐的流动场中的干扰非常重要。但是，在文献中可以找到一些与自助餐基础机制有关的矛盾的理论。因此，这项实验研究的全球目标是洞悉引起自助餐和维持自助餐的机制，遵循假设是导致不稳定的尾随噪声。为此，使用高速层析成像粒子图像赛车和不稳定的压力测量值分析了超临界，二维机翼周围的跨音速场。为了确定声波的影响以及冲击位置，边界层，自由剪切层和声场之间的相互作用，人为地引入了特定属性的声波，并且通过引入高速尾随的边缘来操纵在尾边缘的声场自然产生的声场。尽管非孔尾边缘围绕机翼归档的流程显示自我维持的冲击振荡，但预计当声场通过多孔的尾边缘操纵声场时，流场不会显示出任何冲击振荡。随后，将通过人工引入声波来分析自助餐是否可以重新启动。通过研究两种尾随边缘构型，可以阐明源自后边缘对自助餐现象的声学干扰的影响。因此，这些基本调查旨在证明需要发展低噪声尾随边缘，这不仅与高升效果有关，而且还涉及跨气流流程。

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