Low-dimensional modelling of turbulent jet noise

• Applicant: Professor Dr. Jörn Lothar Sesterhenn, since 10/2010
• Subject Area: Fluid Mechanics
• Term: from 2003 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5470251

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.

• DFG Programme: Research Units
• Subproject of: FOR 508: Noise Generation in Turbulent Flows
• International Connection: France
• Participating Persons: Professor Dr. Pierre Comte; Professor Dr.-Ing. Andreas Dillmann; Professorin Dr. Marie Farge; Professor Dr. Kai Schneider
• Ehemaliger Antragsteller: Professor Dr. Bernd Rainer Noack, from 4/2005 until 10/2010