Background Oriented Schlieren Implementation in a Jet-Surface Interaction Test
Background Oriented Schlieren Implementation in a Jet-Surface Interaction Test
复制标题
射流-表面相互作用测试中面向背景的纹影实施
DOI：
10.2514/6.2013-38
复制
发表时间：
2013
影响因子：
2.4
通讯作者：
A. Fagan
中科院分区：
文献类型：
--
作者：
M. Clem;Clifford A. Brown;A. Fagan
当前和未来的许多飞机设计都依靠机翼或其他飞机表面来屏蔽地面观察者的发动机噪音。然而，关于平面如何与射流相互作用以屏蔽和/或增强射流噪声的可用数据目前是有限的。因此，由美国宇航局基础航空计划固定翼项目支持的喷射-表面相互作用测试旨在提供涵盖与高速喷射流相互作用的各种表面几何形状和位置的实验数据，以支持噪声预测方法的开发。测试的第一阶段在 NASA 格伦研究中心的气动声推进实验室进行，包括验证圆形喷嘴与平面相互作用的噪声预测方案。收集表面的屏蔽侧和反射侧的相控阵数据和远场声学数据。第一阶段的结果表明，当射流在过度膨胀条件下运行时，宽带冲击噪声被表面大大降低，但是，尚不清楚这种降低是否是由于表面冲击单元结构的变化所致。在本研究中，背景导向纹影在射流-表面相互作用测试的第二阶段中实施，以研究平面是否与高速射流相互作用以改变冲击单元结构。针对三种不同板长度的表面的多个轴向和径向位置，获取膨胀不足、理想膨胀和过度膨胀流态的背景定向纹影数据。通过远场噪声测量对这些数据进行分析，将冲击单元结构与表面附近的射流产生的宽带冲击噪声联系起来。
Many current and future aircraft designs rely on the wing or other aircraft surfaces to shield the engine noise from observers on the ground. However the available data regarding how a planar surface interacts with a jet to shield and/or enhance the jet noise are currently limited. Therefore, the Jet-Surface Interaction Tests supported by NASA's Fundamental Aeronautics Program's Fixed Wing Project were undertaken to supply experimental data covering a wide range of surface geometries and positions interacting with high-speed jet flows in order to support the development of noise prediction methods. Phase 1 of the Test was conducted in the Aero-Acoustic Propulsion Laboratory at NASA Glenn Research Center and consisted of validating noise prediction schemes for a round nozzle interacting with a planar surface. Phased array data and far-field acoustic data were collected for both the shielded and reflected sides of the surface. Phase 1 results showed that the broadband shock noise was greatly reduced by the surface when the jet was operated at the over-expanded condition, however, it was unclear whether this reduction was due a change in the shock cell structure by the surface. In the present study, Background Oriented Schlieren is implemented in Phase 2 of the Jet-Surface Interaction Tests to investigate whether the planar surface interacts with the high-speed jet ow to change the shock cell structure. Background Oriented Schlieren data are acquired for under-expanded, ideally-expanded, and over-expanded ow regimes for multiple axial and radial positions of the surface at three different plate lengths. These data are analyzed with far-field noise measurements to relate the shock cell structure to the broadband shock noise produced by a jet near a surface.