Presentation Slides

Abstract:

Aircraft noise is a significant issue affecting communities near airports, especially during take-off. Modern Ultra High Bypass Ratio (UHBR) turbo-fan engines, designed with larger fan diameters and lower rotational speeds, increase the prominence of fan noise over jet noise. Fan noise, characterized by tones and broadband components, necessitates effective noise mitigation strategies. One common method involves using Single Degree of Freedom (SDOF) acoustic liners, which consist of a honeycomb core, perforated face-sheet, and solid backplate. These liners' performance is influenced by various factors, including geometric features and flow conditions. 

While the behavior of liners in response to acoustic waves is well-studied, there is less understanding of their performance under realistic conditions involving both acoustic waves and turbulent flow. Recent studies have shown complex interactions between the acoustic field and turbulent flow, highlighting discrepancies between theoretical models and experimental results. 
This study builds on previous research by conducting high-fidelity numerical simulations using the Lattice-Boltzmann Very-Large-Eddy-Simulation (LB/VLES) solver, SIMULIA PowerFLOW®. The simulations, validated against experimental data, investigate a multi-orifice acoustic liner exposed to turbulent flow and acoustic waves with different amplitude and frequencies. Results indicate that turbulent flow significantly affects the acoustic response of the liner by forming a quasi-steady vortex within the orifices, which reduces the effective open area and alters acoustic wave penetration. The study reveals the importance of considering the direction of acoustic wave propagation relative to the mean flow and the impact of near wake flow from upstream to downstream orifices. 
This research demonstrates the potential of numerical simulations to enhance the understanding of acoustic liner performance under realistic conditions, contributing to developing more effective noise mitigation solutions for modern aircraft engines.

About the Speaker:

Angelo Paduano graduated at Politecnico di Torino with the highest grade in 2023, and he is currently pursuing a PhD at Politecnico di Torino in numerical aeroacoustics.

Angel PADUANO
PhD Student, Politecnico di Torino

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