Multi-Scale Turbulence Structures in Grid-Generated Turbulence for Leading Edge Noise Prediction

Abstract

This study investigates multi-scale turbulence characteristics and their impact on leading-edge noise generation in controlled wind tunnel conditions. Using a turbulence grid mounted in the Acoustic Wind Tunnel Braunschweig (AWB), the inflow turbulence is experimentally characterised and numerically reproduced via large eddy simulations (LES) in OpenFOAM. The analysis focuses on the spatial evolution of turbulence intensity, integral length scales, and energy spectra upstream and downstream of a NACA0012 airfoil. Comparisons between LES and experimental measurements show excellent agreement across key metrics, validating the simulation's fidelity. Vortical structure visualisation and spectral analysis reveal how turbulence decays, distorts, and regenerates through airfoil interaction. These flow dynamics are directly linked to the observed sound pressure level (SPL) spectra and far-field directivity patterns. The findings confirm that grid-generated turbulence drives leading-edge noise through coherent-structure interactions, consistent with classical theories and modern computational predictions.