Deep learning based prediction of urban air mobility noise propagation in urban environment.

A deep learning based method is proposed to predict the urban air mobility (UAM) noise propagation in the urban environment. This method aims to efficiently estimate the noise impact of UAM flights on the complex urban area. The noise hemisphere was created via the comprehensive multirotor noise assessment framework to determine the noise level of UAM.

Prediction-based psychoacoustic analysis of multirotor noise under gusty wind conditions.

This study presents a comprehensive numerical framework for auralizing multirotor noise during complex maneuvers, incorporating rotor tonal and broadband noise prediction, synthesis, and psychoacoustic analysis. Validation studies for various flight scenarios, including single rotors and quadrotors, confirm the capability of this framework in the prediction-based psychoacoustic analysis of multirotor configurations. The primary focus of this research is to assess the flyover and takeoff noise of multirotors under diverse operating conditions.

Development of active noise control simulation with virtual controller based on computational aeroacoustics.

Noise reduction and control research are actively conducted as increasing noise problems compel the stringent noise requirement. Active noise control (ANC) is constructively used in various applications to reduce low-frequency noise. In previous studies, ANC systems were designed based on experiments, requiring extensive effort for effective implementation.

Modeling and Mapping of Combined Noise Annoyance for Aircraft and Road Traffic Based on a Partial Loudness Model.

Complex transportation systems often produce combined exposure to aircraft and road noise. Depending on the noise source, the annoyance response is different, and a masking effect occurs between the noise sources within the combined noise. Considering these characteristics, partial loudness was adopted to evaluate noise annoyance.

Influence of Transportation Noise and Noise Sensitivity on Annoyance: A Cross-Sectional Study in South Korea.

Environmental noise is known to cause noise annoyance. Since noise annoyance is a subjective indicator, other mediators-such as noise sensitivity-may influence its perception. However, few studies have thus far been conducted on noise annoyance in South Korea that consider noise sensitivity and noise level simultaneously.

Application of subharmonics for active sound design of electric vehicles.

The powertrain of electric vehicles generates an unfamiliar acoustical environment for customers. This paper seeks optimal interior sound for electric vehicles based on psychoacoustic knowledge and musical harmonic theory. The concept of inserting a virtual sound, which consists of the subharmonics of an existing high-frequency component, is suggested to improve sound quality.

Numerical modeling of wind turbine aerodynamic noise in the time domain.

Aerodynamic noise from a wind turbine is numerically modeled in the time domain. An analytic trailing edge noise model is used to determine the unsteady pressure on the blade surface. The far-field noise due to the unsteady pressure is calculated using the acoustic analogy theory.

Community response to noise.

Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI) and Frankfurter Fluglarm Index (FFI/FNI) were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate combined noise model. Furthermore, not only negative, but also positive aspects of sound were discussed as soundscape studies.

The effects of long-term exposure to railway and road traffic noise on subjective sleep disturbance.

The exposure-response relationships between subjective annoyance with sleep disturbance from railway trains and road traffic noise were established from an extensive social survey by CENVR (Center for Environmental Noise and Vibration Research) in Korea. The objectives of this research are to determine the long-term effects of noise on sleep and to compare the exposure-response relationships from different noise sources with those from other studies and to elucidate the effects of some modifying factors on subjective responses to noise. From an investigation of the percentage of a highly sleep-disturbed population (%HSD) in response to railway and road traffic noise, it was found that sleep is affected more by railway noise than by road traffic noise.

Noise-induced annoyance from transportation noise: short-term responses to a single noise source in a laboratory.

An experimental study was performed to compare the annoyances from civil-aircraft noise, military-aircraft noise, railway noise, and road-traffic noise. Two-way within-subjects designs were applied in this research. Fifty-two subjects, who were naive listeners, were given various stimuli with varying levels through a headphone in an anechoic chamber.

Broadband impedance boundary conditions for the simulation of sound propagation in the time domain.

An accurate and practical surface impedance boundary condition in the time domain has been developed for application to broadband-frequency simulation in aeroacoustic problems. To show the capability of this method, two kinds of numerical simulations are performed and compared with the analytical/experimental results: one is acoustic wave reflection by a monopole source over an impedance surface and the other is acoustic wave propagation in a duct with a finite impedance wall. Both single-frequency and broadband-frequency simulations are performed within the framework of linearized Euler equations.

Effect of background noise levels on community annoyance from aircraft noise.

A study of community annoyance caused by exposures to civil aircraft noise was carried out in 20 sites around Gimpo and Gimhae international airports to investigate the effect of background noise in terms of dose-effect relationships between aircraft noise levels and annoyance responses under real conditions. Aircraft noise levels were mainly measured using airport noise monitoring systems, B&K type 3597. Social surveys were administered to people living within 100 m of noise measurement sites.

The relationship between railway noise and community annoyance in Korea.

A study of community annoyance caused by exposures to railway noise was carried out in 18 areas along railway lines to accumulate social survey data and assess the relationship between railway noise levels and annoyance responses in Korea. Railway noise levels were measured with portable sound-level meters. Social surveys were administered to people living within 50 m of noise measurement sites.

High frequency formulation for the acoustic power spectrum due to cascade-turbulence interaction.

This paper investigates the noise radiated by a cascade of flat-plate airfoils interacting with homogeneous, isotropic turbulence. An analytic formulation for the spectrum of acoustic power of a two-dimensional flat-plate is derived. The main finding of this paper is that the acoustic power spectrum from the cascade of flat airfoils may be split into two distinct frequency regions of low frequency and high frequency, separated by a critical frequency.