Low noise slat tacks down-selected by NLR

30/06/2021
Low noise slat tacks down-selected by NLR

 

Low noise slat tacks : experimental acoustic down-selection by NLR in in AWT facility

INVENTOR focusses on reducing the noise generated by the slat tracks. The global goal is to better understand the mechanism of slat track noise generation and to assess alternative low noise slat track designs. In a preliminary activity, numerical simulations of the complex mean flow in the slat track area have been achieved, suggesting possible noise generation mechanisms. Then a number of low noise designs have been derived and tested on a 2D high lift wing with a 30° sweep in the AWT aeroacoustic facility at NLR.

Farfield acoustic spectra were obtained from the integration, in the slat track area, of noise maps obtained with a 64-microphone array installed in the flyover plane, showing that this small noise source has a significant contribution to the global airframe noise. First tests on a generic slat track also revealed the influence of the wing cavity and the panel door.
The collected information will help selecting the best low noise slat tracks for further aerodynamic/acoustic tests in ONERA’s F2 facility on a full slat/wing/flap airfoil, in combination with surface porous materials implemented in the slat cove.

 

RANS numerical simulation of the mean flow (left) and test set-up (right)

 

Slat track location (left) – Noise map at frequency 10 kHz

Power integrated spectra of baseline slat tracks. Values are relative to the power integrated spectrum of slat track 2.
Influence of the wing cavity (slat track #1) and the panel door (slat track #3)