Aircraft Noise and Quieter Aviation with Simulation

Introduction

Noise is all around us, and although we encounter it daily, we often don’t think about its impacts on our environment or ourselves unless it disrupts our day-to-day activities. Aeroacoustics, the study of noise generation by turbulent fluid motion, has become a critical area of research across various industries, such as aerospace, automotive, and even architectural engineering. The increasing focus on noise pollution, especially in urban settings, has increased interest in understanding how noise is generated and finding effective strategies to mitigate it.

The aviation sector currently stands at a crossroads. Travel continues to grow, reaching record numbers in 2024.  And with increasingly stringent environmental and sustainability regulations coming down the pipeline, manufacturers need to rethink their approach to aircraft design. In this blog post, we explore the unique challenges of aircraft noise and how advanced simulation technologies can help achieve quieter skies.

The Current Aviation Landscape

Increasing Travel

People want to travel. Total full-year air travel rose 10.4% in 2024 compared to 2023, and 2025 is looking at around an 8% increase (reference link). And as travel has increased, so has noise pollution and the pressure to mitigate it, which is gaining more attention from the public and regulatory bodies. The International Civil Aviation Organization (ICAO) has raised the bar by tightening noise emission limits, most recently by 7 decibels in 2017. Concurrently, initiatives like Europe’s Flightpath 2050 aim for a staggering 65% reduction in aircraft noise emissions by the middle of the century. In addition, noise reduction policies at major airports are becoming more rigorous, as seen with Heathrow’s linking of landing fees to aircraft noise levels..

People have also become much more environmentally conscious over the last several decades and expect a certain level of quality of life, which includes a reduced noise footprint. This focus on sustainability directly impacts airports, including their flight scheduling, routes, and business strategies.

It’s no longer a matter of if but when and how efficiently manufacturers will implement quieter designs across various aircraft models, from traditional jets to innovative eVTOL (electric vertical takeoff and landing) vehicles. So, how do manufacturers address these competing priorities and deliver quieter aircraft?

The Challenges

One of the main hurdles in the quest for quieter aircraft lies in the conventional approach to noise testing, which often occurs in the later design stages. Traditional flight tests can be prohibitively expensive and time-consuming, leaving manufacturers with scant opportunity to make necessary design changes once testing is underway. High-profile projects such as the NASA X-59 supersonic demonstrator and Boom Supersonic’s aircraft endeavors exemplify how noise constraints present formidable barriers to advancements in next-generation aircraft. Without practical early-stage simulations, manufacturers risk incurring substantial redesign costs and regulatory delays, which can stifle innovation, particularly in supersonic and next-generation propulsion systems.

Emerging technologies, especially open-rotor propulsion and eVTOL aircraft, face heightened scrutiny regarding noise levels. Historical attempts at open-rotor concepts, such as the GE36 CROR engine, were shelved primarily due to unacceptable noise levels, even though they offered potential gains in fuel efficiency. As modern designs are re-evaluated, addressing noise targets early in the design process will be critical for success. Regulatory bodies such as the FAA and EASA have imposed stringent noise requirements for eVTOL certification, recognizing that urban noise pollution plays a significant role in public acceptance of these innovations.

Advances in Simulation

A promising solution to combat these challenges lies in advancing noise simulation methodologies. Traditional acoustic simulation techniques often necessitate a significant degree of simplification in aircraft geometry, which can lead to incomplete or inaccurate predictions regarding noise generation. Modern simulation tools allow for fully detailed modeling without the need for de-featuring. This capability substantially reduces preprocessing time while eliminating uncertainties associated with simplified features. Whether the analysis involves landing gear, high-lift systems in commercial airliners, or the complex configurations of eVTOL aircraft with multiple rotors, these advanced techniques ensure that no critical noise sources are overlooked during the design phase.

At the heart of these advanced simulation technologies is the Lattice Boltzmann Method (LBM), which holds considerable advantages over traditional Computational Fluid Dynamics (CFD) approaches. The streamlined meshing process intrinsic to LBM significantly cuts preparation time—from weeks to mere days—even for highly intricate geometries. Additionally, LBM adeptly manages transient, highly unsteady flows with minimal numerical dissipation, allowing for accurate aeroacoustic predictions without the need for supplementary acoustic modeling. Compared to Large Eddy Simulation (LES), the solver operates one to two orders of magnitude faster while maintaining similar accuracy levels, making it an optimal choice for detailed aeroacoustic studies across various flight conditions.

Application Templates

The application templates are perhaps the most important advancement we have made with SIMULIA PowerFLOW. With automatic 3D meshing and templated workflows, high-fidelity simulations can be set up quickly and efficiently, eliminating the need for time-consuming manual refinements.

We have noise workflows for several A&D applications, from landing gear to high-lift noise, from isolated rotor noise, to upcoming concepts like open rotor noise in commercial aviation, from jet noise, to full eVTOL/Drone noise in urban scenarios. Our customers highly appreciate these workflows, as they are well-documented, researched, and tested step-by-step procedures that give users the confidence to make accurate predictions. Some of these workflows even have fully automated simulation templates for pre- and post-processing that result in significant efficiency gains. Read more about these templates in the e-book: Quieter Skies with Simulation.

Conclusion

The implications of adopting robust simulation solutions are profound. By integrating advanced simulation tools early in the design process, manufacturers can make informed decisions, ultimately boosting design quality and reducing the likelihood of costly revisions later in development. This proactive approach accelerates the path to quieter skies and aligns with regulatory requirements more seamlessly, enhancing compliance and market readiness.

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