Aircraft noise

About: Aircraft noise is a research topic. Over the lifetime, 3051 publications have been published within this topic receiving 32039 citations.

On Noise Assessment for Blended Wing Body Aircraft

Abstract: A system noise study is presented for the blended-wing-body (BWB) aircraft configured with advanced technologies that are projected to be available in the 2025 timeframe of the NASA N+2 definition. This system noise assessment shows that the noise levels of the baseline configuration, measured by the cumulative Effective Perceived Noise Level (EPNL), have a large margin of 34 dB to the aircraft noise regulation of Stage 4. This confirms the acoustic benefits of the BWB shielding of engine noise, as well as other projected noise reduction technologies, but the noise margins are less than previously published assessments and are short of meeting the NASA N+2 noise goal. In establishing the relevance of the acoustic assessment framework, the design of the BWB configuration, the technical approach of the noise analysis, the databases and prediction tools used in the assessment are first described and discussed. The predicted noise levels and the component decomposition are then analyzed to identify the ranking order of importance of various noise components, revealing the prominence of airframe noise, which holds up the levels at all three noise certification locations and renders engine noise reduction technologies less effective. When projected airframe component noise reduction is added to the HWB configuration, it is shown that the cumulative noise margin to Stage 4 can reach 41.6 dB, nearly at the NASA goal. These results are compared with a previous NASA assessment with a different study framework. The approaches that yield projections of such low noise levels are discussed including aggressive assumptions on future technologies, assumptions on flight profile management, engine installation, and component noise reduction technologies. It is shown that reliable predictions of component noise also play an important role in the system noise assessment. The comparisons and discussions illustrate the importance of practical feasibilities and constraints in aircraft system noise studies, which include aerodynamic performance, propulsion efficiency, flight profile limitation and many other factors. For a future aircraft concept to achieve the NASA N+2 noise goal it will require a range of fully successful noise reduction technology developments.

Equitable Aircraft Noise-Abatement Departure Procedures

Abstract: This paper deals with the optimization of aircraft noise-abatement departure procedures. A multicriteria optimization strategy is presented, where the fairness of the optimal trajectories is assessed vis-a-vis the different noise-sensitive locations around the airport of study. This equitable optimization is formulated as the minimization of the maximum noise-annoyance deviation regarding all considered locations. This strategy is complemented with an iterative lexicographic optimization algorithm which, in turn, guarantees the Pareto efficiency condition of the final solution. Aircraft operating costs are also considered by neglecting the marginal benefits of noise reduction below a certain threshold value. An application example is shown (as an illustrative case) based on a departure of runway 02 at Girona airport in Catalonia, Spain. The results show the feasibility of this technique, which is intended to be used by procedure designers or airport authorities.