Flow and Acoustics of a Coaxial Nozzle: a Sensitivity Study to the Inlet Boundary Conditions.

Authors: Mihaescu, M, Gutmark, E., Szasz, R.Z., Fuchs, L.F.
Document Type: Article
Pubstate: Published
Journal: 44th AIAA Aerospace Sciences Meeting and Exhibit.
Volume: AIAA 2006-619   19 pages
Year: 2006


The jet noise generated by the high velocity hot stream exhausting from a jet engine represents a major component of the aircraft noise. Reductions in jet noise has been achieved by using high bypass turbo-fan engines. To solve numerically this problem the flow and acoustic fields generated by two coaxial jets are considered. Large Eddy Simulation (LES) is used to handle the non-isothermal turbulent flow field, while for the acoustic field a wave equation with source terms provided by the instantaneous LES is employed. The effects of the inlet boundary conditions on the flow and acoustics are assessed in this paper. A comparison of the computed mean flow field and the SPL with experimental data show excellent agreement at distances of over a few jet diameters downstream of the the jet exit plane. In the proximal part the agreement is less good. However, the discrepancy between the simulations and the experiments is less than the corresponding variations due to the uncertainties in the experimental boundary conditions.