Jet engine manufacturers have known for some time that mixer design has a strong influence on jet noise, but the correlation between the two is unclear. The Reynolds-averaged Navier Stokes (RANS) computed steady-state flowfields of several mixers for which the far-field noise characteristics are known are analyzed. Three mixers with different lobe penetration heights are examined. The WIND computational fluid dynamics (CFD) code is used and compared with results from recent experiments conducted at the NASA John H. Glenn Research Center at Lewis Field. The Menter shear stress transport turbulence model and computational meshes of 1.9 million grid points are used for the comparisons. The turbulent kinetic energy profiles predicted by CFD are in good qualitative agreement with experimental data. Inferences are also made as to what correlations can be drawn between the RANS computed flowfield and the experimentally determined far-field noise and how this information may be used as an aid in mixer design.

Jet engine manufacturers have known for some time that mixer design has a strong influence on jet noise, but the correlation is unclear. In this paper we analyze the Reynolds averaged Navier Stokes (RANS) computed steady state flow fields of several mixer geometries for which the far field noise characteristics are known. We use the WIND CFD code and compare with recent experiments conducted at the NASA Glenn Research Center. Inferences are then made as to what correlations can be drawn between the RANS computed flow field and the experimentally determined far-field noise and how this information may be used as an aid in mixer design. For example, streamwise vortices hitting the nozzle wall and the free shear layer (as happens for the high penetration case) may limit the noise at low angles.

Jet engine manufacturers have known for some time that mixer design has a strong in∞uence on jet noise, but the correlation is unclear. We utilize Reynolds averaged Navier Stokes (RANS) solutions to investigate the suitability of various jet mixer geometries in reducing the far fleld noise level of internally mixed turbofan engines. This paper analyzes the computed steady state ∞ow fleld of a mixer for which the far fleld noise characteristics is known. Inferences are then made as to what correlations can be drawn between the ∞ow structure and the far-fleld noise generated.