Contribution
The Cause of Flap Side Edge Noise: Numerical Validation and Verification
* Presenting author
Abstract:
For an aircraft with fully deployed flaps, the flap side edge noise could be identified as one of the major noise sources for the final phase of landing approach. In order to come up with effective noise reduction measures, an experiment was set up in the AWB wind tunnel (Braunschweig), where a realistic large scale isolated flap side edge was tested with various low-noise modifications. The simulations were performed for the baseline and simplified side edges, for the purpose of visualising turbulent structures and understanding the mechanisms of side edge noise. For the proof of concept, our method of choice is a cut-cell wall-modelled Large Eddy Simulation (LES), implemented in the MGLET (KM-Turbulenz) code. The above is used to validate an advanced stochastics-based modelling approach developed by DLR, which relies on solving a Forced Linear Advection Diffusion (FLAD) transport equation in 3D, where mean turbulent quantities are supplied from high quality RANS simulations, performed for the selected flap side edge configurations. Far-field acoustic spectra are then compared at individual microphone positions between LES and stochastics-based simulations, and cross compared to the measurements.