Zn Wang

LES-RANS of installed ultra-high bypass-ratio coaxial jet aeroacoustics with a finite span wing-flap geometry and flight stream-part 1: Round nozzle

© 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. The jet noise produced by aeroengines is a critical topic in engine design. Large-Eddy Simulation (LES) and hybrid LES-Reynolds-Averaged Navier-Stokes (LES-RANS), provides a method to increase understanding of influences on the noise produced. Installed jet noise modelling has received less attention than isolated jet noise yet is becoming more important for design. Here, using LES-RANS, a coaxial nozzle with an ultra-high bypass-ratio of 15 is studied with and without a wing-flap geometry. The bypass ratio leads the nozzle to become extremely close to the wing-flap geometry introducing strong installation effects. Two different flap deflections of 8 and 14 degrees are contrasted with an isolated round nozzle. A flight stream is applied and an FWH surface placement procedure for installed jets is proposed. The installed cases generate more directional noise at mid-low frequencies as the presence of the flap trailing edge produces a strong dipole source. Second order space-time correlations reveal length and time scales in the flow. Fourth order space-time correlations indicate increasing magnitudes of the dominant noise source components with in increasing flap angle and may lead to improved acoustics models.

Research data supporting Predictive LES for jet aeroacoustics - current approach and industrial application

This flow and acoustic data for the jet LES relates to the figures in the paper as in the respective file names. Variables are given in each ASCII file. All data is contained within the .zip file.

Large-eddy simulation of the flight stream effects on single stream heated jets

© 2017 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc. Large-eddy simulation (LES) is performed on single stream hot jets to investigate the flight stream effects. The hot jet with forward flight Mach number 0.3 is investigated by contrasting with a static hot jet. The far-field sound is predicted using Ffowcs Williams-Hawkings (FW-H) equations. The prediction shows agreement with the experimental measurements in both near field flows and far field sounds. The flight stream effects are shown in far-field sound level and spectrum and in the near field sound source and turbulent flow properties.