Numerical Investigation of Broadband Slat Noise Attenuation with Acoustic liner Treatment
16
Numerical Investigation of Broadband Slat Noise Attenuation with Acoustic liner Treatment University of Southampton Southampton, UK Authors: Zhaokai Ma, Xin Zhang and Malcolm Smith Technical Supervisor: Stephen Chow Airbus, Bristol, UK
description
Numerical Investigation of Broadband Slat Noise Attenuation with Acoustic liner Treatment. Authors: Zhaokai Ma, Xin Zhang and Malcolm Smith. University of Southampton Southampton, UK. Technical Supervisor: Stephen Chow. Airbus, Bristol, UK. Introduction Numerical models - PowerPoint PPT Presentation
Transcript of Numerical Investigation of Broadband Slat Noise Attenuation with Acoustic liner Treatment
Numerical Investigation of Broadband Slat Noise Attenuation with Acoustic liner
Treatment
University of SouthamptonSouthampton, UK
Authors: Zhaokai Ma, Xin Zhang and Malcolm Smith
Technical Supervisor: Stephen Chow
Airbus, Bristol, UK
Outline
Introduction Numerical models Computational results
– Aerodynamic flow field– Noise radiation
Summary and future work
Approach noise of a Airbus A340-300 aircraft
Slat noise is one of the dominating sources of aircraft noise during landing
Introduction
Hybrid noise prediction methods
Introduction
Numerical models
Governing equations: Navier-Stokes equations
Spatial discretization: 4th, 6th -order compact schemes
Time integration: Implicit 2nd -order LU method
Explicit 4th –order Runge-Kutta method
Turbulence model: Spalart-Allmaras, DES, LES
Computational aeroacoustic solver: SotonCAA
Linearized acoustic solver: SotonLEE
Radiation Model: FW-H
3D slat broadband noise simulation
A view of the grid around the high lift wing
Slat in landing conditions
Flap in retracted position
Freestream Mach = 0.2
Angle of attack = 12 deg.
Re = 3.6×106
Total grid cells 5.5 million
Δz/c=0.002, 26 points at span-
wise
Implicit solver, 2nd order
temporal accuracy and 6th
order spatial accuracy
CFL=15, 5 subiterations
Smagorinsky LES subgrid
model
Computation setup for LES
Q iso surface colored with z-vorticity
3D slat broadband noise simulation
z-vorticity contours near the slat cove region
Rapid distortion of coherent structures via mean-flow straining
Secondary separation
Cove vortex
Vortex merging
Edge scattering
3D slat broadband noise simulation
3D slat broadband noise simulation
Location of the mixing layer profile monitoring lines
Mean velocity profile on the monitoring lines
3D slat broadband noise simulation
Velocity fluctuations along the monitoring line A
3D TKE and velocity fluctuations along the monitoring line C
3D slat broadband noise simulation
Spanwise correlation of velocity fluctuations along monitoring line 1.
Spanwise correlation of velocity fluctuations along monitoring line 2.
3D slat broadband noise simulation
Power spectral density at different monitor points
A view of the grid for LES sources driven APE calculation
3D APE with LES
calculated sources
Total grid cells 1.2 million
Δz/c=0.002, 26 points at
span-wise
Explicit solver, 4nd order
temporal accuracy and 6th
order spatial accuracy
Source terms:
Ti me domain impedance
boundary condition of
Fung et. al.
3D slat broadband noise simulation Computation setup for LES source driven APE
3D slat broadband noise simulation
A view of the liner treatment and the grid near the slat cove
Pressure perturbation around the high lift wing
Comparison of the farfield directivity
3D slat broadband noise simulation
Attenuation along the frequency
Summary and future work
Summary Broadband slat noise generation was simulated using
LES Broadband slat noise attenuation ability of acoustic
liners was explored Future work
Refined grid calculation of LESDifferent definitions of acoustic sourcesOptimization of the acoustic liner for broadband noise
