Low-dimensional modelling of turbulent jet noise

湍流射流噪声的低维建模

• 批准号: 5405923
• 负责人: Professor Dr. Jörn Lothar Sesterhenn, since 10/2010
• 金额: --
• 依托单位: Institut für Aeordynamik und Strömungstechnik (IAS)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5405923?language=en
• 关键词: Low; dimensional; modelling; turbulent; jet

The goal of this project is to achieve a mechanistic understanding of jet noise generation and to identify means of noise reduction. Highly accurate simulations of this research group are employed to distill the major physical processes in low-dimensional coherent-structure representations. The dynamics of the large-scale coherent structures are described by Galerkin and vortex models. These models shall be enhanced by a hierarchy of acoustic analogies, ranging from a Howe analogy for the transversally radiated noise to a Möhring analogy capturing also the directivity. A detailed comparison between simulations and models allow to monitor the applicability of approximations. The low-dimensional models are the test bed for the physical understanding achieved from the simulation data and enabie quick explorative sensitivity studies. These parametrics may shed light on the flow features which influence the far-field noise most sensitively and thus need to be carefully resolved in a simulation. In addition, 'quiet' and 'noisy' flow structures shall be identified from inexpensive exploratory studies with low-dimensional models and shall be excited in more expensive, well-resolved simulations of actuated jets.

本项目的目标是实现喷气噪声产生的机理的理解，并确定降噪的手段。本研究小组的高精度模拟被用来提取低维相干结构表示中的主要物理过程。用伽辽金模型和涡旋模型描述了大尺度相干结构的动力学过程。这些模型应通过声学类比的层次结构来增强，从横向辐射噪声的Howe类比到捕获方向性的Möhring类比。模拟和模型之间的详细比较允许监测近似值的适用性。低维模型是从模拟数据中获得物理理解的测试平台，可以快速进行探索性敏感性研究。这些参数可能会揭示影响远场噪声最敏感的流动特征，因此需要在模拟中仔细解决。此外，“安静”和“嘈杂”的流动结构应确定从廉价的探索性研究与低维模型，并应激发在更昂贵的，以及解决模拟驱动射流。