Modeling of the Flow and Acoustical Field due to a Single Jet with Chevrons.

Authors: Mihaescu, M, Gutmark, E.
Document Type: Article
Pubstate: Published
Journal: 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit.
Volume: AIAA 2007-5757   9 pages
Year: 2007


The turbulent jets exhausting from jet engines are the main sources of aircraft noise. Finding new jet noise suppression methods and developing cheap and accurate jet noise prediction approaches was and is the major interest for many research groups. In the present paper the acoustic field generated by flow unsteadiness in an isothermal turbulent jet with forced mixers is determined using a hybrid approach. The computational domain includes in the first instance the near-field ”source” region and a small part of the acoustical region. The dynamics of the turbulent jet and its mixing with the surrounding air generate the acoustic sources that are calculated, on this restricted grid, by solving the flow field with Large Eddy Simulation (LES) approach. The sound radiated in the far-field is computed on a much larger domain by solving an inhomogeneous wave equation with acoustic source terms provided by near-field LES calculations. The flow and the acoustic data from the single jet case with chevrons are compared with those obtained from a circular jet, showing the acoustic benefit when chevrons are used on the nozzle.