Computational Analyses Of Propulsion Aeroacoustics For Mixed Flow Nozzle Pylon Installation At Takeoff

Computational Analyses of Propulsion Aeroacoustics for Mixed Flow Nozzle Pylon Installation at Takeoff

Computational Analyses of Propulsion Aeroacoustics for Mixed Flow Nozzle Pylon Installation at Takeoff

A CFD analyses is presented for a set of baseline and noise suppression mixed flow nozzles with and without a pylon installation. The five model configurations are as follows; a baselinecore/fan dual-stream nozzle with an external plug, a chevron mixer nozzle with a peak on the symmetry plane with external plug, both of the above nozzles with an installed bifurcatingpylon and lastly a clocked chevron mixer nozzle such that a trough is aligned with the center of the pylon. The fluid flow is simulated by solving the asymptotically steady, compressible, Reynolds-averaged Navier-Stokes equations using an implicit, up-wind, flux-difference splitting finite volume scheme and standard two equation k-epsilon turbulence model with a linear stress representation. All computations are performed using the multiblock, parallel, structuredcode PAB3D. Results indicate that the clocked chevron with pylon case achieves the most optimal levels of average and peak turbulence kinetic energy and vorticity and therefore is expected to be the quietest of the five configurations tested. Further study is required to refine expressions which are indicative of noise and mate these with rigorous noise prediction models.Massey, Steven J. and Waithe, Kenrich A.Langley Research CenterCOMPUTATIONAL FLUID DYNAMICS; PLUG NOZZLES; AEROACOUSTICS; ANALYSIS (MATHEMATICS); FINITE VOLUME METHOD; FLUX DIFFERENCE SPLITTING; NOISE PREDICTION; TAKEOFF; NAVIER-STOKES EQUATION; NOISE REDUCTION; TURBULENCE; REYNOLDS EQUATION

Computational Analysis of Propulsion Aeroacoustics for Mixed Flow Nozzle Pylon Installation at Takeoff ... Nasa